charon_lib/pretty/

fmt_with_ctx.rs

//! Utilities for pretty-printing (u)llbc.
use crate::{
    ast,
    formatter::*,
    ids::IndexVec,
    llbc_ast::{self as llbc, *},
    transform::utils::GenericsSource,
    ullbc_ast::{self as ullbc, *},
    utils::{TAB_INCR, repeat_except_first},
};
use either::Either;
use itertools::Itertools;
use std::{
    borrow::Cow,
    fmt::{self, Debug, Display},
};

pub struct WithCtx<'a, C, T: ?Sized> {
    val: &'a T,
    ctx: &'a C,
}

impl<'a, C, T: ?Sized> Display for WithCtx<'a, C, T>
where
    T: FmtWithCtx<C>,
{
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.val.fmt_with_ctx(self.ctx, f)
    }
}

/// Format the AST type as a string.
pub trait FmtWithCtx<C> {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result;

    /// Returns a struct that implements `Display`. This allows the following:
    /// ```text
    ///     println!("{}", self.with_ctx(ctx));
    /// ```
    fn with_ctx<'a>(&'a self, ctx: &'a C) -> WithCtx<'a, C, Self> {
        WithCtx { val: self, ctx }
    }

    fn to_string_with_ctx(&self, ctx: &C) -> String {
        self.with_ctx(ctx).to_string()
    }
}

macro_rules! impl_display_via_ctx {
    ($ty:ty) => {
        impl Display for $ty {
            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                self.fmt_with_ctx(&FmtCtx::new(), f)
            }
        }
    };
}
macro_rules! impl_debug_via_display {
    ($ty:ty) => {
        impl Debug for $ty {
            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                <_ as Display>::fmt(self, f)
            }
        }
    };
}

fn fmt_where_clauses<'a, I>(clauses: I, indent: &'a str) -> impl Display + 'a
where
    I: IntoIterator,
    I::Item: Display,
{
    let clauses = clauses
        .into_iter()
        .map(|clause| clause.to_string())
        .collect_vec();
    std::fmt::from_fn(move |f| {
        if !clauses.is_empty() {
            write!(f, "\n{indent}where")?;
            for (i, clause) in clauses.iter().enumerate() {
                let sep = if i + 1 == clauses.len() { ";" } else { "," };
                write!(f, "\n{indent}{TAB_INCR}{clause}{sep}")?;
            }
        }
        Ok(())
    })
}

//------- Impls, sorted by name --------

impl<C: AstFormatter> FmtWithCtx<C> for AbortKind {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            AbortKind::Panic(name) => {
                write!(f, "panic")?;
                if let Some(name) = name {
                    write!(f, "({})", name.with_ctx(ctx))?;
                }
                Ok(())
            }
            AbortKind::UndefinedBehavior => write!(f, "undefined_behavior"),
            AbortKind::UnwindTerminate => write!(f, "unwind_terminate"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Abi {
    fn fmt_with_ctx(&self, _ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.rust_name())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for BuiltinAssertKind {
    fn fmt_with_ctx(&self, _ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            BuiltinAssertKind::BoundsCheck { .. } => write!(f, "bounds_check"),
            BuiltinAssertKind::Overflow(..) => write!(f, "overflow"),
            BuiltinAssertKind::OverflowNeg(..) => write!(f, "overflow_neg"),
            BuiltinAssertKind::DivisionByZero(..) => write!(f, "division_by_zero"),
            BuiltinAssertKind::RemainderByZero(..) => write!(f, "remainder_by_zero"),
            BuiltinAssertKind::MisalignedPointerDereference { .. } => {
                write!(f, "misaligned_pointer_dereference")
            }
            BuiltinAssertKind::NullPointerDereference => write!(f, "null_pointer_dereference"),
            BuiltinAssertKind::NullReferenceCreated => write!(f, "null_reference_created"),
            BuiltinAssertKind::InvalidEnumConstruction(..) => {
                write!(f, "invalid_enum_construction")
            }
            BuiltinAssertKind::ResumedAfterReturn => write!(f, "resumed_after_return"),
            BuiltinAssertKind::ResumedAfterDrop => write!(f, "resumed_after_drop"),
            BuiltinAssertKind::ResumedAfterPanic => write!(f, "resumed_after_panic"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ItemId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match ctx.get_crate() {
            None => write!(f, "{self}"),
            Some(translated) => translated.item_short_name(*self).fmt_with_ctx(ctx, f),
        }
    }
}

impl Display for ItemId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        let s = match self {
            ItemId::Type(x) => x.to_pretty_string(),
            ItemId::Fun(x) => x.to_pretty_string(),
            ItemId::Global(x) => x.to_pretty_string(),
            ItemId::TraitDecl(x) => x.to_pretty_string(),
            ItemId::TraitImpl(x) => x.to_pretty_string(),
        };
        f.write_str(&s)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for MaybeAssocItemId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            MaybeAssocItemId::Free(id) => id.fmt_with_ctx(ctx, f),
            MaybeAssocItemId::Assoc(trait_id, item_id) => {
                write!(f, "{}::", ItemId::TraitDecl(*trait_id).with_ctx(ctx),)?;
                ctx.format_assoc_item_name(f, *trait_id, *item_id)
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ItemRef<'_> {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ItemRef::Type(d) => write!(f, "{}", d.with_ctx(ctx)),
            ItemRef::Fun(d) => write!(f, "{}", d.with_ctx(ctx)),
            ItemRef::Global(d) => write!(f, "{}", d.with_ctx(ctx)),
            ItemRef::TraitDecl(d) => write!(f, "{}", d.with_ctx(ctx)),
            ItemRef::TraitImpl(d) => write!(f, "{}", d.with_ctx(ctx)),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Assert {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "assert({} == {})",
            self.cond.with_ctx(ctx),
            self.expected,
        )?;
        if let Some(check_kind) = &self.check_kind {
            write!(f, " ({})", check_kind.with_ctx(ctx))?;
        }
        Ok(())
    }
}

impl<T> Binder<T> {
    /// Format the parameters and contents of this binder and returns the resulting strings.
    fn fmt_split<'a, C>(&'a self, ctx: &'a C) -> (String, String)
    where
        C: AstFormatter,
        T: FmtWithCtx<C::Reborrow<'a>>,
    {
        self.fmt_split_with(ctx, |ctx, x| x.to_string_with_ctx(ctx))
    }
    /// Format the parameters and contents of this binder and returns the resulting strings.
    fn fmt_split_with<'a, C>(
        &'a self,
        ctx: &'a C,
        fmt_inner: impl FnOnce(&C::Reborrow<'a>, &T) -> String,
    ) -> (String, String)
    where
        C: AstFormatter,
    {
        let ctx = &ctx.push_binder(Cow::Borrowed(&self.params));
        (
            self.params.fmt_with_ctx_single_line(ctx),
            fmt_inner(ctx, &self.skip_binder),
        )
    }
}

impl Display for OverflowMode {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            OverflowMode::Panic => write!(f, "panic"),
            OverflowMode::Wrap => write!(f, "wrap"),
            OverflowMode::UB => write!(f, "ub"),
        }
    }
}

impl Display for BinOp {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            BinOp::BitXor => write!(f, "^"),
            BinOp::BitAnd => write!(f, "&"),
            BinOp::BitOr => write!(f, "|"),
            BinOp::Eq => write!(f, "=="),
            BinOp::Lt => write!(f, "<"),
            BinOp::Le => write!(f, "<="),
            BinOp::Ne => write!(f, "!="),
            BinOp::Ge => write!(f, ">="),
            BinOp::Gt => write!(f, ">"),
            BinOp::Add(mode) => write!(f, "{}.+", mode),
            BinOp::Sub(mode) => write!(f, "{}.-", mode),
            BinOp::Mul(mode) => write!(f, "{}.*", mode),
            BinOp::Div(mode) => write!(f, "{}./", mode),
            BinOp::Rem(mode) => write!(f, "{}.%", mode),
            BinOp::AddChecked => write!(f, "checked.+"),
            BinOp::SubChecked => write!(f, "checked.-"),
            BinOp::MulChecked => write!(f, "checked.*"),
            BinOp::Shl(mode) => write!(f, "{}.<<", mode),
            BinOp::Shr(mode) => write!(f, "{}.>>", mode),
            BinOp::Cmp => write!(f, "cmp"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for llbc::Block {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for st in &self.statements {
            st.fmt_with_ctx(ctx, f)?;
        }
        Ok(())
    }
}

const LLBC_UNWIND_PREFIX: &str = "↳⚡ ";

fn fmt_llbc_unwind_block<C: AstFormatter>(
    ctx: &C,
    f: &mut fmt::Formatter<'_>,
    on_unwind: &llbc::Block,
) -> fmt::Result {
    let tab = ctx.indent();
    let block = on_unwind.to_string_with_ctx(&ctx.reset_indent());
    let mut lines = block.lines();
    if let Some(first) = lines.next() {
        write!(f, "\n{tab}{LLBC_UNWIND_PREFIX}{first}")?;
        let ctx = ctx.increase_indent();
        let tab = ctx.indent();
        for line in lines {
            write!(f, "\n{tab}{line}")?;
        }
    }
    Ok(())
}

/// With `include_safety`, add a comment line if this isn't safe.
fn fmt_safety_comment<C: AstFormatter>(
    ctx: &C,
    f: &mut fmt::Formatter<'_>,
    x: &impl HasSafety,
) -> fmt::Result {
    let tab = ctx.indent();
    match ctx.get_crate().filter(|_| ctx.include_safety()) {
        Some(krate) => match x.safety(krate) {
            Safety::Safe => Ok(()),
            Safety::Unsafe => writeln!(f, "{tab}// unsafe"),
            Safety::Unknown(reason) => writeln!(f, "{tab}// unknown safety: {reason}"),
        },
        None => Ok(()),
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ullbc::BlockData {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        for statement in &self.statements {
            statement.fmt_with_ctx(ctx, f)?;
        }
        write!(f, "{};", self.terminator.with_ctx(ctx))?;
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ast::Body {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let tab = ctx.indent();
        write!(f, "\n{tab}")?;
        match self {
            Body::Unstructured(body) => {
                let body = body.with_ctx(ctx);
                write!(f, "{{\n{body}{tab}}}")
            }
            Body::Structured(body) => {
                let body = body.with_ctx(ctx);
                write!(f, "{{\n{body}{tab}}}")
            }
            Body::Extern(name) => write!(f, "= <extern:{name}>"),
            Body::Intrinsic { name, .. } => write!(f, "= <intrinsic:{name}>"),
            Body::Opaque => write!(f, "= <opaque>"),
            Body::Missing => write!(f, "= <missing>"),
            Body::Error(error) => write!(f, "= error(\"{}\")", error.msg),
            Body::TargetDispatch(targets) => {
                writeln!(f, "= target_dispatch {{")?;
                for (target, fun) in targets {
                    let fun = fun.with_ctx(ctx);
                    writeln!(f, "{tab}{TAB_INCR}{target} => {fun},")?;
                }
                write!(f, "{tab}}}")
            }
        }
    }
}

impl Display for BorrowKind {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        // Reuse the derived `Debug` impl to get the variant name.
        write!(f, "{self:?}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Call {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let dest = self.dest.with_ctx(ctx);
        let func = self.func.with_ctx(ctx);
        let args = self.args.iter().map(|x| x.with_ctx(ctx)).format(", ");
        write!(f, "{dest} = {func}({args})")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for AsmRegister {
    fn fmt_with_ctx(&self, _ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            AsmRegister::Explicit(reg) => write!(f, "{:?}", reg.as_str()),
            AsmRegister::Class(class) => write!(f, "{class}"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for AsmOperand {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            AsmOperand::In { reg, value } => {
                write!(f, "in({}) {}", reg.with_ctx(ctx), value.with_ctx(ctx))
            }
            AsmOperand::Out { reg, late, place } => {
                let op = if *late { "lateout" } else { "out" };
                write!(f, "{op}({}) ", reg.with_ctx(ctx))?;
                match place {
                    Some(place) => write!(f, "{}", place.with_ctx(ctx)),
                    None => write!(f, "_"),
                }
            }
            AsmOperand::InOut {
                reg,
                late,
                in_value,
                out_place,
            } => {
                let op = if *late { "inlateout" } else { "inout" };
                write!(
                    f,
                    "{op}({}) {} => ",
                    reg.with_ctx(ctx),
                    in_value.with_ctx(ctx)
                )?;
                match out_place {
                    Some(place) => write!(f, "{}", place.with_ctx(ctx)),
                    None => write!(f, "_"),
                }
            }
            AsmOperand::Const(value) => write!(f, "const {}", value.with_ctx(ctx)),
            AsmOperand::SymFn(value) => write!(f, "sym {}", value.with_ctx(ctx)),
            AsmOperand::SymStatic(value) => write!(f, "sym {}", value.with_ctx(ctx)),
            AsmOperand::Label(branch) => write!(f, "label(branch {})", branch.index()),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for InlineAsm {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mac = match self.kind {
            AsmKind::Asm => "asm",
            AsmKind::NakedAsm => "naked_asm",
        };
        let mut template = String::new();
        for piece in &self.template {
            match piece {
                AsmTemplatePiece::Text(text) => {
                    for c in text.chars() {
                        if c == '{' || c == '}' {
                            template.push(c);
                        }
                        template.push(c);
                    }
                }
                AsmTemplatePiece::Placeholder {
                    operand_id,
                    modifier,
                    ..
                } => {
                    template.push('{');
                    template.push_str(&operand_id.index().to_string());
                    if let Some(modifier) = modifier {
                        template.push(':');
                        template.push(*modifier);
                    }
                    template.push('}');
                }
            }
        }
        write!(f, "{mac}!({template:?}")?;
        for operand in &self.operands {
            write!(f, ", {}", operand.with_ctx(ctx))?;
        }
        let options = &self.options;
        let flags = [
            (options.pure, "pure"),
            (options.nomem, "nomem"),
            (options.readonly, "readonly"),
            (options.preserves_flags, "preserves_flags"),
            (options.noreturn, "noreturn"),
            (options.nostack, "nostack"),
            (options.att_syntax, "att_syntax"),
            (options.may_unwind, "may_unwind"),
        ];
        let flags = flags
            .iter()
            .filter_map(|(set, name)| set.then_some(*name))
            .collect_vec();
        if !flags.is_empty() {
            write!(f, ", options({})", flags.iter().format(", "))?;
        }
        write!(f, ")")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for UnsizingMetadata {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            UnsizingMetadata::Length(len) => write!(f, "{}", len.with_ctx(ctx)),
            UnsizingMetadata::VTable(_, vtable) => {
                write!(f, "{}", vtable.with_ctx(ctx))
            }
            UnsizingMetadata::VTableUpcast(fields) => {
                write!(f, " at [")?;
                let fields = fields.iter().map(|x| format!("{}", x.index())).format(", ");
                write!(f, "{fields}]")
            }
            UnsizingMetadata::Unknown => {
                write!(f, "?")
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for CastKind {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            CastKind::Scalar(tgt) => write!(f, "cast<{tgt}>"),
            CastKind::PtrExposeProvenance => write!(f, "cast_expose"),
            CastKind::PtrWithExposedProvenance(tgt) => {
                write!(f, "cast_with_exposed<{}>", tgt.with_ctx(ctx))
            }
            CastKind::FnDefToFnPtr => write!(f, "fn_def_to_fn_ptr"),
            CastKind::FnPtrToUnsafe => write!(f, "fn_ptr_to_unsafe"),
            CastKind::Subtype(tgt) => write!(f, "subtype<{}>", tgt.with_ctx(ctx)),
            CastKind::RawPtr(tgt) => write!(f, "cast<{}>", tgt.with_ctx(ctx)),
            CastKind::Unsize(tgt, meta, _) => write!(
                f,
                "unsize_cast<{}, {}>",
                tgt.with_ctx(ctx),
                meta.with_ctx(ctx)
            ),
            CastKind::Transmute(tgt) => write!(f, "transmute<{}>", tgt.with_ctx(ctx)),
            CastKind::Concretize(tgt, _) => write!(f, "concretize<{}>", tgt.with_ctx(ctx)),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ClauseDbVar {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ctx.format_bound_var(f, *self, "TraitClause", |_| None)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ConstGenericDbVar {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ctx.format_bound_var(f, *self, "@ConstGeneric", |v| Some(v.name.clone()))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ConstGenericParam {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "const {} : {}", self.name, self.ty.with_ctx(ctx))
    }
}

impl Display for DeBruijnId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        write!(f, "{}", self.index)
    }
}

impl<Id: Display> Display for DeBruijnVar<Id> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Bound(dbid, varid) => write!(f, "Bound({dbid}, {varid})"),
            Self::Free(varid) => write!(f, "Free({varid})"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for DeclarationGroup {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        use DeclarationGroup::*;
        match self {
            Type(g) => write!(f, "Type decls group: {}", g.with_ctx(ctx)),
            Fun(g) => write!(f, "Fun decls group: {}", g.with_ctx(ctx)),
            Global(g) => write!(f, "Global decls group: {}", g.with_ctx(ctx)),
            TraitDecl(g) => write!(f, "Trait decls group: {}", g.with_ctx(ctx)),
            TraitImpl(g) => write!(f, "Trait impls group: {}", g.with_ctx(ctx)),
            Mixed(g) => write!(f, "Mixed group: {}", g.with_ctx(ctx)),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Discriminator {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Discriminator::Known(variant_id) => ctx.format_current_variant_name(f, *variant_id),
            Discriminator::Invalid => write!(f, "invalid"),
            Discriminator::Branch {
                offset,
                children,
                fallback,
                ..
            } => {
                write!(f, "read at offset {} {{ ", offset.with_ctx(ctx))?;
                for (range, child) in children {
                    if range.start() == range.end() {
                        write!(f, "{}", range.start())?;
                    } else {
                        write!(f, "{}..={}", range.start(), range.end())?;
                    }
                    write!(f, " => {}, ", child.with_ctx(ctx))?;
                }
                write!(f, "_ => {} }}", fallback.with_ctx(ctx))
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for DynPredicate {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let params = &self.binder.params;
        let ctx = &ctx.push_binder(Cow::Borrowed(params));
        let GenericParams {
            regions,
            types,
            const_generics,
            trait_clauses,
            regions_outlive,
            types_outlive,
            trait_type_constraints,
        } = params;
        assert!(regions.is_empty());
        assert!(const_generics.is_empty());
        assert!(regions_outlive.is_empty());
        assert_eq!(types.len(), 1);

        // Format the clauses with their assoc types, e.g. `Iterator<Item = ...>`.
        let mut cstrs_per_clause: IndexVec<TraitClauseId, Vec<String>> =
            trait_clauses.map_ref(|_| vec![]);
        for cstr in trait_type_constraints {
            let mut tgt_clause = None;
            let (_, cstr) = cstr.fmt_split_with(ctx, |ctx, cstr| {
                let mut path = vec![];
                let mut tref = &cstr.trait_ref;
                loop {
                    match &tref.kind {
                        TraitRefKind::ParentClause(parent_trait_ref, clause_id, _) => {
                            path.push(*clause_id);
                            tref = parent_trait_ref;
                        }
                        &TraitRefKind::Clause(DeBruijnVar::Bound(_, clause_id), _) => {
                            tgt_clause = Some(clause_id);
                            break;
                        }
                        _ => unreachable!(),
                    }
                }
                let ty = cstr.ty.with_ctx(ctx);
                let path_fmt = path.iter().map(|id| id.format_as_implied()).format("::");
                std::fmt::from_fn(|f| {
                    write!(f, "{path_fmt}")?;
                    if !path.is_empty() {
                        write!(f, "::")?;
                    }
                    ctx.format_assoc_type_name(f, cstr.trait_ref.trait_id(), cstr.type_id)?;
                    write!(f, " = {ty}")?;
                    Ok(())
                })
                .to_string()
            });
            if let Some(cstrs) = cstrs_per_clause.get_mut(tgt_clause.unwrap()) {
                cstrs.push(cstr);
            }
        }
        let trait_clauses = trait_clauses.iter().map(|clause| {
            let cstrs = &cstrs_per_clause[clause.clause_id];
            clause.trait_.fmt_as_for_with(ctx, |ctx, pred| {
                let (_, pred) = pred.split_self();
                let trait_id = pred.id.with_ctx(ctx);
                let generics = if pred.generics.has_explicits() || !cstrs.is_empty() {
                    let xs = pred
                        .generics
                        .fmt_explicits(ctx)
                        .map(Either::Left)
                        .chain(cstrs.iter().map(Either::Right))
                        .format(", ");
                    format!("<{}>", xs)
                } else {
                    String::new()
                };
                format!("{trait_id}{generics}")
            })
        });

        let types_outlive = types_outlive
            .iter()
            .filter(|x| !x.skip_binder.1.is_erased())
            .map(|x| {
                x.fmt_as_for_with(ctx, |ctx, types_outlive| {
                    types_outlive.1.to_string_with_ctx(ctx)
                })
            });
        let clauses = trait_clauses.chain(types_outlive).format(" + ");
        write!(f, "{clauses}")
    }
}

impl_display_via_ctx!(Field);
impl<C: AstFormatter> FmtWithCtx<C> for Field {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}: {}", self.name, self.ty.with_ctx(ctx))
    }
}

impl Display for FileName {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            FileName::Virtual(path_buf) | FileName::Local(path_buf) => {
                write!(f, "{}", path_buf.display())
            }
            FileName::NotReal(name) => write!(f, "{}", name),
        }
    }
}

impl Display for FloatTy {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            FloatTy::F16 => write!(f, "f16"),
            FloatTy::F32 => write!(f, "f32"),
            FloatTy::F64 => write!(f, "f64"),
            FloatTy::F128 => write!(f, "f128"),
        }
    }
}

impl Display for FloatValue {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        let v = &self.value;
        let ty = self.ty;
        write!(f, "{v}{ty}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for FnOperand {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            FnOperand::Regular(func) => write!(f, "{}", func.with_ctx(ctx)),
            FnOperand::Dynamic(op, regions) => {
                write!(f, "({})", op.with_ctx(ctx))?;
                if !regions.is_empty() {
                    write!(
                        f,
                        "<{}>",
                        regions.iter().map(|r| r.with_ctx(ctx)).format(", ")
                    )?;
                }
                Ok(())
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for FnPtr {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self.kind.as_ref() {
            FnPtrKind::Fun(def_id) => write!(f, "{}", def_id.with_ctx(ctx))?,
            FnPtrKind::Trait(trait_ref, method_id) => {
                write!(f, "{}::", trait_ref.with_ctx(ctx))?;
                ctx.format_method_name(f, trait_ref.trait_id(), *method_id)?;
            }
        };
        write!(f, "{}", self.generics.with_ctx(ctx))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for FunDecl {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut keyword = String::new();
        if self.signature.is_unsafe {
            keyword.push_str("unsafe ");
        }
        if !self.signature.abi.is_rust() {
            keyword.push_str(&format!("extern \"{}\" ", self.signature.abi.with_ctx(ctx)));
        }
        keyword.push_str("fn");
        self.item_meta
            .fmt_item_intro(f, ctx, &keyword, self.def_id)?;

        // Update the context
        let ctx = &ctx.set_generics(&self.generics);

        // Generic parameters
        let (params, preds) = self.generics.fmt_with_ctx_with_trait_clauses(ctx);
        write!(f, "{params}")?;

        // Arguments
        let n_args = self.signature.inputs.len();
        let args_of_locals = |l: &Locals| {
            let ctx = ctx.set_locals(l);
            l.locals
                .iter()
                .skip(1)
                .take(n_args)
                .map(|l| format!("{}", l.index.with_ctx(&ctx)))
                .collect::<Vec<String>>()
        };

        let arg_names = match &self.body {
            Body::Unstructured(body) => args_of_locals(&body.locals),
            Body::Structured(body) => args_of_locals(&body.locals),
            Body::Intrinsic { arg_names, .. } => arg_names
                .iter()
                .enumerate()
                .map(|(i, name)| {
                    let id = LocalId::new(i + 1);
                    match name {
                        Some(name) => format!("{name}_{id}"),
                        None => format!("_{id}"),
                    }
                })
                .collect(),
            Body::Error(..)
            | Body::Extern(..)
            | Body::Missing
            | Body::Opaque
            | Body::TargetDispatch(..) => (0..n_args)
                .map(|i| format!("{}", LocalId::new(i + 1).with_ctx(ctx)))
                .collect(),
        };
        let mut args: Vec<String> = Vec::new();
        for (ty, name) in self.signature.inputs.iter().zip(arg_names) {
            args.push(format!("{}: {}", name, ty.with_ctx(ctx)));
        }
        let args = args.join(", ");
        if self.signature.is_variadic {
            if args.is_empty() {
                write!(f, "(...)")?;
            } else {
                write!(f, "({args}, ...)")?;
            }
        } else {
            write!(f, "({args})")?;
        }

        // Return type
        if !self.signature.output.is_unit() {
            write!(f, " -> {}", self.signature.output.with_ctx(ctx))?;
        };
        write!(f, "{preds}")?;
        write!(f, "{}", self.body.with_ctx(ctx))?;

        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for FunDeclId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ItemId::from(*self).fmt_with_ctx(ctx, f)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for FunDeclRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let id = self.id.with_ctx(ctx);
        let generics = self.generics.with_ctx(ctx);
        write!(f, "{id}{generics}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for RegionBinder<FunSig> {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Update the bound regions
        let ctx = &ctx.push_bound_regions(&self.regions);
        let FunSig {
            is_unsafe,
            abi,
            is_variadic,
            inputs,
            output,
        } = &self.skip_binder;

        if *is_unsafe {
            write!(f, "unsafe ")?;
        }

        if !abi.is_rust() {
            write!(f, "extern \"{}\" ", abi.with_ctx(ctx))?;
        }

        write!(f, "fn")?;
        let params = self.fmt_params_with_ctx(ctx);
        if !params.is_empty() {
            write!(f, "<{params}>")?;
        }
        let is_empty = inputs.is_empty();
        let inputs = inputs.iter().map(|x| x.with_ctx(ctx)).format(", ");
        if *is_variadic {
            if is_empty {
                write!(f, "(...)")?;
            } else {
                write!(f, "({inputs}, ...)")?;
            }
        } else {
            write!(f, "({inputs})")?;
        }
        if !output.is_unit() {
            let output = output.with_ctx(ctx);
            write!(f, " -> {output}")?;
        }
        Ok(())
    }
}

impl<Id: Copy, C: AstFormatter> FmtWithCtx<C> for GDeclarationGroup<Id>
where
    Id: FmtWithCtx<C>,
{
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        use GDeclarationGroup::*;
        match self {
            NonRec(id) => write!(f, "Non rec: {}", id.with_ctx(ctx)),
            Rec(ids) => {
                let ids = ids.iter().map(|id| id.with_ctx(ctx)).format(", ");
                write!(f, "Rec: {}", ids)
            }
        }
    }
}

impl GenericArgs {
    pub(crate) fn fmt_explicits<'a, C: AstFormatter>(
        &'a self,
        ctx: &'a C,
    ) -> impl Iterator<Item = impl Display + 'a> {
        let regions = self.regions.iter().map(|x| x.with_ctx(ctx));
        let types = self.types.iter().map(|x| x.with_ctx(ctx));
        let const_generics = self.const_generics.iter().map(|x| x.with_ctx(ctx));
        regions.map(Either::Left).chain(
            types
                .map(Either::Left)
                .chain(const_generics.map(Either::Right))
                .map(Either::Right),
        )
    }

    pub(crate) fn fmt_implicits<'a, C: AstFormatter>(
        &'a self,
        ctx: &'a C,
    ) -> impl Iterator<Item = impl Display + 'a> {
        self.trait_refs.iter().map(|x| x.with_ctx(ctx))
    }
}

impl_display_via_ctx!(GenericArgs);
impl_debug_via_display!(GenericArgs);
impl<C: AstFormatter> FmtWithCtx<C> for GenericArgs {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if self.has_explicits() {
            write!(f, "<{}>", self.fmt_explicits(ctx).format(", "))?;
        }
        if self.has_implicits() {
            write!(f, "[{}]", self.fmt_implicits(ctx).format(", "))?;
        }
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for RegionArgs {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if self.is_empty() {
            Ok(())
        } else {
            write!(f, "<{}>", self.iter().map(|r| r.with_ctx(ctx)).format(", "))
        }
    }
}

impl GenericParams {
    fn formatted_params<'a, C>(&'a self, ctx: &'a C) -> impl Iterator<Item = impl Display + 'a>
    where
        C: AstFormatter,
    {
        let regions = self.regions.iter().map(|x| x.with_ctx(ctx));
        let types = self.types.iter().map(|x| x.with_ctx(ctx));
        let const_generics = self.const_generics.iter().map(|x| x.with_ctx(ctx));
        regions.map(Either::Left).chain(
            types
                .map(Either::Left)
                .chain(const_generics.map(Either::Right))
                .map(Either::Right),
        )
    }

    fn formatted_clauses<'a, C>(&'a self, ctx: &'a C) -> impl Iterator<Item = impl Display + 'a>
    where
        C: AstFormatter,
    {
        let trait_clauses = self.trait_clauses.iter().map(|x| x.to_string_with_ctx(ctx));
        let types_outlive = self
            .types_outlive
            .iter()
            .enumerate()
            .map(|(i, x)| format!("TypeOutlives{i}: {}", x.fmt_as_for(ctx)));
        let regions_outlive = self
            .regions_outlive
            .iter()
            .enumerate()
            .map(|(i, x)| format!("RegionOutlives{i}: {}", x.fmt_as_for(ctx)));
        let type_constraints = self
            .trait_type_constraints
            .iter_enumerated()
            .map(|(i, x)| format!("TypeConstraint{i}: {}", x.fmt_as_for(ctx)));
        trait_clauses.map(Either::Left).chain(
            types_outlive
                .chain(regions_outlive)
                .chain(type_constraints)
                .map(Either::Right),
        )
    }

    pub fn fmt_with_ctx_with_trait_clauses<C>(&self, ctx: &C) -> (String, String)
    where
        C: AstFormatter,
    {
        let tab = ctx.indent();
        let params = if self.has_explicits() {
            let params = self.formatted_params(ctx).format(", ");
            format!("<{}>", params)
        } else {
            String::new()
        };
        let clauses = if self.has_predicates() {
            let clauses = self
                .formatted_clauses(ctx)
                .map(|x| format!("\n{tab}{TAB_INCR}{x},"))
                .format("");
            format!("\n{tab}where{clauses}")
        } else {
            String::new()
        };
        (params, clauses)
    }

    pub fn fmt_with_ctx_single_line<C>(&self, ctx: &C) -> String
    where
        C: AstFormatter,
    {
        if self.is_empty() {
            String::new()
        } else {
            let params = self
                .formatted_params(ctx)
                .map(Either::Left)
                .chain(self.formatted_clauses(ctx).map(Either::Right))
                .format(", ");
            format!("<{}>", params)
        }
    }
}

impl_debug_via_display!(GenericParams);
impl Display for GenericParams {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        write!(f, "{}", self.fmt_with_ctx_single_line(&FmtCtx::new()))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for GenericsSource {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            GenericsSource::Item(id) => write!(f, "{}", id.with_ctx(ctx)),
            GenericsSource::Method(id, name) => write!(f, "{}::{name}", id.with_ctx(ctx)),
            GenericsSource::TraitType(id, name) => {
                write!(f, "{}::", id.with_ctx(ctx))?;
                ctx.format_assoc_type_name(f, *id, *name)
            }
            GenericsSource::Builtin => write!(f, "<builtin>"),
            GenericsSource::Other => write!(f, "<unknown>"),
        }
    }
}

impl<T> GExprBody<T> {
    fn fmt_with_ctx_and_callback<C: AstFormatter>(
        &self,
        ctx: &C,
        f: &mut fmt::Formatter<'_>,
        fmt_body: impl FnOnce(
            &mut fmt::Formatter<'_>,
            &<<C as AstFormatter>::Reborrow<'_> as AstFormatter>::Reborrow<'_>,
            &T,
        ) -> fmt::Result,
    ) -> fmt::Result {
        // Update the context
        let ctx = &ctx.set_locals(&self.locals);
        let ctx = &ctx.increase_indent();
        let tab = ctx.indent();

        // Format the local variables
        for v in &self.locals.locals {
            write!(f, "{tab}")?;
            write!(f, "let {}: {};", v.index.with_ctx(ctx), v.ty.with_ctx(ctx))?;

            write!(f, " // ")?;
            if v.index.is_zero() {
                write!(f, "return")?;
            } else if self.locals.is_return_or_arg(v.index) {
                write!(f, "arg #{}", v.index.index())?
            } else {
                match &v.name {
                    Some(_) => write!(f, "local")?,
                    None => write!(f, "anonymous local")?,
                }
            }
            if let Some(place) = &v.drop_flag_for {
                write!(f, "; drop flag for {}", place.with_ctx(ctx))?;
            }
            writeln!(f)?;
        }

        fmt_body(f, ctx, &self.body)?;

        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for GExprBody<llbc_ast::Block> {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Inference fails when this is a closure.
        fn fmt_body<C: AstFormatter>(
            f: &mut fmt::Formatter<'_>,
            ctx: &<<C as AstFormatter>::Reborrow<'_> as AstFormatter>::Reborrow<'_>,
            body: &Block,
        ) -> Result<(), fmt::Error> {
            writeln!(f)?;
            body.fmt_with_ctx(ctx, f)?;
            Ok(())
        }
        self.fmt_with_ctx_and_callback(ctx, f, fmt_body::<C>)
    }
}
impl<C: AstFormatter> FmtWithCtx<C> for GExprBody<ullbc_ast::BodyContents> {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Inference fails when this is a closure.
        fn fmt_body<C: AstFormatter>(
            f: &mut fmt::Formatter<'_>,
            ctx: &<<C as AstFormatter>::Reborrow<'_> as AstFormatter>::Reborrow<'_>,
            body: &IndexVec<ullbc::BlockId, BlockData>,
        ) -> Result<(), fmt::Error> {
            let tab = ctx.indent();
            let ctx = &ctx.increase_indent();
            for (bid, block) in body.iter_enumerated() {
                let kind = match block.kind {
                    ullbc::UnwindKind::Regular => "",
                    ullbc::UnwindKind::Cleanup => " (cleanup)",
                    ullbc::UnwindKind::Terminate => " (terminate)",
                };
                writeln!(f)?;
                writeln!(f, "{tab}bb{}{kind}: {{", bid.index())?;
                writeln!(f, "{}", block.with_ctx(ctx))?;
                writeln!(f, "{tab}}}")?;
            }
            Ok(())
        }
        self.fmt_with_ctx_and_callback(ctx, f, fmt_body::<C>)
    }
}

impl<C> FmtWithCtx<C> for GlobalDecl
where
    C: AstFormatter,
{
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let keyword = match self.global_kind {
            GlobalKind::Static {
                is_mut,
                is_thread_local,
                is_safe,
            } => {
                let unsafe_ = if is_safe { "" } else { "unsafe " };
                let name = if is_thread_local {
                    "thread_local"
                } else {
                    "static"
                };
                let mut_ = if is_mut { " mut" } else { "" };
                &*format!("{unsafe_}{name}{mut_}")
            }
            GlobalKind::AnonConst | GlobalKind::NamedConst => "const",
            GlobalKind::VTable => "vtable",
        };
        self.item_meta
            .fmt_item_intro(f, ctx, keyword, self.def_id)?;

        // Update the context with the generics
        let ctx = &ctx.set_generics(&self.generics);

        // Translate the parameters and the trait clauses
        let (params, preds) = self.generics.fmt_with_ctx_with_trait_clauses(ctx);

        // Type
        let ty = self.ty.with_ctx(ctx);
        write!(f, "{params}: {ty}")?;

        // Predicates
        write!(f, "{preds}")?;
        if self.generics.has_predicates() {
            writeln!(f)?;
        }
        write!(f, " ")?;

        // Value
        let value = self.value.with_ctx(ctx);
        write!(f, "= {value}")?;
        if !self.ptr_metadata.ty().is_unit() {
            write!(f, " with_metadata({})", self.ptr_metadata.with_ctx(ctx))?;
        }

        if ctx.include_layouts() {
            let (size, align) = (self.size.with_ctx(ctx), self.align.with_ctx(ctx));
            write!(f, "\n// size: {size}, align: {align}")?;
        }

        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for GlobalDeclId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ItemId::from(*self).fmt_with_ctx(ctx, f)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for GlobalDeclRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let id = self.id.with_ctx(ctx);
        let generics = self.generics.with_ctx(ctx);
        write!(f, "{id}{generics}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ImplElem {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{{")?;
        match self {
            ImplElem::Ty(bound_ty) => {
                // Just printing the generics (not the predicates)
                let ctx = ctx.set_generics(&bound_ty.params);
                bound_ty.skip_binder.fmt_with_ctx(&ctx, f)?
            }
            ImplElem::Trait(impl_id) => {
                match ctx.get_crate().and_then(|tr| tr.trait_impls.get(*impl_id)) {
                    None => write!(f, "impl#{impl_id}")?,
                    Some(timpl) => {
                        // We need to put the first type parameter aside: it is the type for which
                        // we implement the trait.
                        let ctx = &ctx.set_generics(&timpl.generics);
                        let negative = if timpl.is_negative { "!" } else { "" };
                        let mut impl_trait = timpl.impl_trait.clone();
                        match impl_trait
                            .generics
                            .types
                            .remove_and_shift_ids(TypeVarId::ZERO)
                        {
                            Some(self_ty) => {
                                let self_ty = self_ty.with_ctx(ctx);
                                let impl_trait = impl_trait.with_ctx(ctx);
                                write!(f, "impl {negative}{impl_trait} for {self_ty}")?;
                            }
                            // TODO(mono): A monomorphized trait doesn't take arguments.
                            None => {
                                let impl_trait = impl_trait.with_ctx(ctx);
                                write!(f, "impl {negative}{impl_trait}")?;
                            }
                        }
                    }
                }
            }
        }
        write!(f, "}}")
    }
}

impl Display for IntTy {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            IntTy::Isize => write!(f, "isize"),
            IntTy::I8 => write!(f, "i8"),
            IntTy::I16 => write!(f, "i16"),
            IntTy::I32 => write!(f, "i32"),
            IntTy::I64 => write!(f, "i64"),
            IntTy::I128 => write!(f, "i128"),
        }
    }
}

impl Display for UIntTy {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            UIntTy::Usize => write!(f, "usize"),
            UIntTy::U8 => write!(f, "u8"),
            UIntTy::U16 => write!(f, "u16"),
            UIntTy::U32 => write!(f, "u32"),
            UIntTy::U64 => write!(f, "u64"),
            UIntTy::U128 => write!(f, "u128"),
        }
    }
}

impl Display for IntegerTy {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            IntegerTy::Signed(int_ty) => write!(f, "{int_ty}"),
            IntegerTy::Unsigned(uint_ty) => write!(f, "{uint_ty}"),
        }
    }
}

fn trait_impl_short_name<C: AstFormatter>(ctx: &C, impl_id: TraitImplId) -> Option<&Name> {
    ctx.get_crate()
        .and_then(|tr| tr.short_names.get(&ItemId::TraitImpl(impl_id)))
        .filter(|name| matches!(name.name.first(), Some(PathElem::Ident(..))))
}

impl ItemMeta {
    /// Format the start of an item definition, up to the name.
    pub fn fmt_item_intro<C: AstFormatter>(
        &self,
        f: &mut fmt::Formatter<'_>,
        ctx: &C,
        keyword: &str,
        id: impl Into<ItemId>,
    ) -> fmt::Result {
        let tab = ctx.indent();
        let id = id.into();
        let mut name = &self.name;
        let mut name_is_full = true;
        if let Some(tr) = ctx.get_crate()
            && let Some(short_name) = tr.short_names.get(&id)
        {
            name = short_name;
            name_is_full = false;
        } else if self
            .name
            .name
            .iter()
            .filter_map(|ne| ne.as_impl()?.as_trait())
            .any(|impl_id| trait_impl_short_name(ctx, *impl_id).is_some())
        {
            name_is_full = false;
        };
        if !name_is_full {
            writeln!(f, "// Full name: {}", self.name.full_name(ctx))?;
        }
        if ctx.include_safety()
            && let Some(tr) = ctx.get_crate()
            && let Some(item) = tr.get_item(id)
        {
            let unsafe_to = [
                ("declare", item.is_unsafe_to_declare(tr)),
                (
                    "call",
                    matches!(item, ItemRef::Fun(d) if d.is_unsafe_to_call(tr)),
                ),
                (
                    "access",
                    matches!(item, ItemRef::Global(d) if d.is_unsafe_to_access(tr)),
                ),
                (
                    "implement",
                    matches!(item, ItemRef::TraitDecl(d) if d.is_unsafe_to_implement(tr)),
                ),
            ];
            for (action, _) in unsafe_to.into_iter().filter(|(_, is_unsafe)| *is_unsafe) {
                writeln!(f, "{tab}// unsafe to {action}")?;
            }
        }

        for attr in &self.attr_info.attributes {
            // Doc-comments are long and don't affect the semantics; skip them.
            if attr.is_doc_comment() {
                continue;
            }
            writeln!(f, "{tab}{}", attr.with_ctx(ctx))?;
        }
        if let Some(id) = &self.lang_item {
            writeln!(f, "{tab}#[lang_item({id:?})]")?;
        }
        if let Some(id) = &self.diagnostic_item {
            writeln!(f, "{tab}#[diagnostic_item(\"{id}\")]")?;
        }
        write!(f, "{tab}")?;
        if self.attr_info.public {
            write!(f, "pub ")?;
        }
        if self.is_extern {
            write!(f, "extern ")?;
        }
        write!(f, "{keyword} {}", name.with_ctx(ctx))
    }
}

impl_display_via_ctx!(InhabitedPredicate);
impl<C: AstFormatter> FmtWithCtx<C> for InhabitedPredicate {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self.kind() {
            InhabitedPredicateKind::True => write!(f, "true"),
            InhabitedPredicateKind::False => write!(f, "false"),
            InhabitedPredicateKind::ConstIsZero(value) => {
                write!(f, "{} == 0", value.with_ctx(ctx))
            }
            InhabitedPredicateKind::GenericType(ty) => {
                write!(f, "if_inhabited({})", ty.with_ctx(ctx))
            }
            InhabitedPredicateKind::And(predicates) => {
                write!(
                    f,
                    "({})",
                    predicates.iter().map(|p| p.with_ctx(ctx)).format(" && ")
                )
            }
            InhabitedPredicateKind::Or(predicates) => {
                write!(
                    f,
                    "({})",
                    predicates.iter().map(|p| p.with_ctx(ctx)).format(" || ")
                )
            }
        }
    }
}

impl_display_via_ctx!(Layout);
impl<C: AstFormatter> FmtWithCtx<C> for Layout {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let tab = ctx.indent();
        writeln!(f, "{tab}size: {},", self.size.with_ctx(ctx))?;
        writeln!(f, "{tab}align: {},", self.align.with_ctx(ctx))?;
        match &self.discriminator {
            Some(discriminator) => {
                writeln!(f, "{tab}discriminator: {},", discriminator.with_ctx(ctx))?
            }
            None => writeln!(f, "{tab}discriminator: none,")?,
        }
        writeln!(f, "{tab}inhabited: {},", self.inhabited.with_ctx(ctx))?;
        writeln!(f, "{tab}variants: [")?;
        let ctx1 = &ctx.increase_indent();
        let tab1 = ctx1.indent();
        for (variant_id, layout) in self.variant_layouts.iter_enumerated() {
            write!(f, "{tab1}")?;
            ctx1.format_current_variant_name(f, variant_id)?;
            write!(f, ": ")?;
            match layout {
                Some(layout) => writeln!(f, "{},", layout.with_ctx(&(ctx1, variant_id)))?,
                None => writeln!(f, "none,")?,
            }
        }
        writeln!(f, "{tab}],")?;
        write!(f, "{tab}{},", self.repr)
    }
}

impl Display for ScalarTy {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            ScalarTy::Integer(ty) => write!(f, "{ty}"),
            ScalarTy::Float(ty) => write!(f, "{ty}"),
            ScalarTy::Char => write!(f, "char"),
            ScalarTy::Bool => write!(f, "bool"),
        }
    }
}

impl Display for Loc {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        write!(f, "{}:{}", self.line, self.col)
    }
}

impl Display for Local {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // We display both the variable name and its id because some
        // variables may have the same name (in different scopes)
        if let Some(name) = &self.name {
            write!(f, "{name}")?
        }
        write!(f, "_{}", self.index)?;
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for LocalId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ctx.format_local_id(f, *self)
    }
}

impl Display for MetadataValue {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let name = match self {
            MetadataValue::DynSize => "dyn_size",
            MetadataValue::DynAlign => "dyn_align",
            MetadataValue::SliceLength => "slice_length",
        };
        write!(f, "{name}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Name {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Reset generics to avoid names being displayed differently depending on the current
        // binding level.
        let ctx = &ctx.no_generics();
        let name = self.name.iter().map(|x| x.with_ctx(ctx)).format("::");
        write!(f, "{}", name)
    }
}

impl Name {
    /// Print the full name, which is different from printing a `Name` since that will use the
    /// short name for impls.
    fn full_name<'a, C: AstFormatter + 'a>(&'a self, ctx: &'a C) -> impl Display + 'a {
        std::fmt::from_fn(move |f| {
            let ctx = &ctx.no_generics();
            let name = self
                .name
                .iter()
                .map(|elem| match elem {
                    PathElem::Impl(impl_elem) => Either::Left(impl_elem.with_ctx(ctx)),
                    _ => Either::Right(elem.with_ctx(ctx)),
                })
                .format("::");
            write!(f, "{name}")
        })
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for NullOp {
    fn fmt_with_ctx(&self, _ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let op = match self {
            NullOp::UbChecks => "ub_checks",
            NullOp::OverflowChecks => "overflow_checks",
            NullOp::ContractChecks => "contract_checks",
        };
        write!(f, "{op}")
    }
}

impl_display_via_ctx!(Operand);
impl<C: AstFormatter> FmtWithCtx<C> for Operand {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Operand::Copy(p) => write!(f, "copy {}", p.with_ctx(ctx)),
            Operand::Move(p) => write!(f, "move {}", p.with_ctx(ctx)),
            Operand::Const(c) => write!(f, "const {}", c.with_ctx(ctx)),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for OffsetExpr {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self.chosen {
            Some(chosen) => write!(f, "{chosen}")?,
            None => write!(f, "?")?,
        }
        if let Some(guarantee) = &self.guarantee {
            write!(f, " (guaranteed: {})", guarantee.with_ctx(ctx))?;
        }
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for OffsetGuarantee {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            OffsetGuarantee::AtOffset(offset) => write!(f, "{}", offset.with_ctx(ctx)),
            OffsetGuarantee::GuaranteedAlignment(align) => {
                write!(f, "aligned({})", align.with_ctx(ctx))
            }
            OffsetGuarantee::ReprCField(FieldPredecessor::Field(field)) => {
                write!(f, "repr_c_after({field})")
            }
            OffsetGuarantee::ReprCField(FieldPredecessor::Tag) => write!(f, "repr_c_after_tag"),
        }
    }
}

impl<C: AstFormatter, T, U> FmtWithCtx<C> for OutlivesPred<T, U>
where
    T: FmtWithCtx<C>,
    U: FmtWithCtx<C>,
{
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}: {}", self.0.with_ctx(ctx), self.1.with_ctx(ctx))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for PathElem {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            PathElem::Ident(s, d) => {
                write!(f, "{s}")?;
                if !d.is_zero() {
                    write!(f, "#{}", d)?;
                }
                Ok(())
            }
            PathElem::Impl(impl_elem) => {
                if let ImplElem::Trait(impl_id) = impl_elem
                    && let Some(short_name) = trait_impl_short_name(ctx, *impl_id)
                {
                    return write!(f, "{}", short_name.with_ctx(ctx));
                }
                write!(f, "{}", impl_elem.with_ctx(ctx))
            }
            PathElem::Builtin(BuiltinPathElem::Tuple(n), _) => {
                let fields = std::iter::repeat_n("_", *n).format(", ");
                let trailing_comma = if *n == 1 { "," } else { "" };
                write!(f, "({fields}{trailing_comma})")
            }
            PathElem::Builtin(elem, d) => {
                if !elem.is_rust_name() {
                    write!(f, "{{")?;
                }
                write!(f, "{}", elem.ident())?;
                if !d.is_zero() {
                    write!(f, "#{d}")?;
                }
                if !elem.is_rust_name() {
                    write!(f, "}}")?;
                }
                Ok(())
            }
            PathElem::Instantiated(binder) => {
                // Anonymize all parameters.
                let underscore = "_".to_string();
                let params = GenericParams {
                    regions: binder.params.regions.map_ref(|x| RegionParam {
                        name: Some(underscore.clone()),
                        ..*x
                    }),
                    types: binder.params.types.map_ref(|x| TypeParam {
                        name: underscore.clone(),
                        ..*x
                    }),
                    const_generics: binder.params.const_generics.map_ref(|x| ConstGenericParam {
                        name: underscore.clone(),
                        ty: x.ty.clone(),
                        index: x.index,
                    }),
                    trait_clauses: binder.params.trait_clauses.clone(),
                    ..GenericParams::empty()
                };
                let ctx = &ctx.push_binder(Cow::Owned(params));
                write!(
                    f,
                    "<{}>",
                    binder.skip_binder.fmt_explicits(ctx).format(", ")
                )
            }
            PathElem::Target(target) => write!(f, "{target}"),
        }
    }
}

impl_display_via_ctx!(Place);
impl<C: AstFormatter> FmtWithCtx<C> for Place {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match &self.kind {
            PlaceKind::Local(var_id) => write!(f, "{}", var_id.with_ctx(ctx)),
            PlaceKind::Global(global_ref) => global_ref.fmt_with_ctx(ctx, f),
            PlaceKind::Projection(subplace, projection) => {
                let sub = subplace.with_ctx(ctx);
                match projection {
                    ProjectionElem::Deref => write!(f, "(*{sub})"),
                    ProjectionElem::Field(variant_id, field_id) => {
                        fmt_field_projection(ctx, f, sub, subplace.ty(), *variant_id, *field_id)
                    }
                    ProjectionElem::PtrMetadata => write!(f, "{sub}.metadata"),
                    ProjectionElem::Index {
                        offset,
                        from_end: true,
                        ..
                    } => write!(f, "{sub}[-{}]", offset.with_ctx(ctx)),
                    ProjectionElem::Index {
                        offset,
                        from_end: false,
                        ..
                    } => write!(f, "{sub}[{}]", offset.with_ctx(ctx)),
                    ProjectionElem::Subslice {
                        from,
                        to,
                        from_end: true,
                        ..
                    } => write!(f, "{sub}[{}..-{}]", from.with_ctx(ctx), to.with_ctx(ctx)),
                    ProjectionElem::Subslice {
                        from,
                        to,
                        from_end: false,
                        ..
                    } => write!(f, "{sub}[{}..{}]", from.with_ctx(ctx), to.with_ctx(ctx)),
                    ProjectionElem::Offset {
                        bytes, in_bounds, ..
                    } => {
                        let method = if *in_bounds {
                            "offset"
                        } else {
                            "wrapping_offset"
                        };
                        write!(f, "{sub}.{method}!({})", bytes.with_ctx(ctx))
                    }
                }
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for GlobalPlace {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match &self.kind {
            GlobalPlaceKind::Global(prov) => prov.fmt_with_ctx(ctx, f),
            GlobalPlaceKind::Value(value) => value.fmt_with_ctx(ctx, f),
            GlobalPlaceKind::Projection(subplace, projection) => {
                let sub = subplace.with_ctx(ctx);
                match projection {
                    ConstProjectionElem::Field(variant_id, field_id) => {
                        fmt_field_projection(ctx, f, sub, &subplace.ty, *variant_id, *field_id)
                    }
                    ConstProjectionElem::Index(i) => write!(f, "{sub}[{i}]"),
                    ConstProjectionElem::Subslice { from, to } => write!(f, "{sub}[{from}..{to}]"),
                    ConstProjectionElem::Offset {
                        count,
                        ty,
                        in_bounds,
                        ..
                    } => {
                        let method = if *in_bounds {
                            "offset"
                        } else {
                            "wrapping_offset"
                        };
                        match ty {
                            None => write!(f, "{sub}.{method}!({count})"),
                            Some(ty) => write!(
                                f,
                                "{sub}.{method}!({count} * size_of::<{}>())",
                                ty.with_ctx(ctx)
                            ),
                        }
                    }
                }
            }
        }
    }
}

/// Formats the projection of field `field_id` of `sub`, which has type `sub_ty`.
fn fmt_field_projection<C: AstFormatter>(
    ctx: &C,
    f: &mut fmt::Formatter<'_>,
    sub: impl Display,
    sub_ty: &Ty,
    variant_id: Option<VariantId>,
    field_id: FieldId,
) -> fmt::Result {
    let Some(tref) = sub_ty.as_adt() else {
        return write!(f, "{sub}.{field_id}");
    };
    match variant_id {
        None => write!(f, "{sub}.")?,
        Some(variant_id) => {
            write!(f, "({sub} as variant ")?;
            ctx.format_enum_variant(f, tref.id, variant_id)?;
            write!(f, ").")?;
        }
    }
    ctx.format_field_name(f, tref.id, variant_id, field_id)
}

impl<C: AstFormatter> FmtWithCtx<C> for PolyTraitDeclRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.fmt_as_for(ctx))
    }
}

impl PolyTraitDeclRef {
    fn format_as_pred<'a, C: AstFormatter + 'a>(&'a self, ctx: &'a C) -> impl Display + 'a {
        self.fmt_as_for_with(ctx, |ctx, pred| format!("({})", pred.format_as_pred(ctx)))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for PolyTraitRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.0.fmt_as_for(ctx))
    }
}

impl PolyTraitRef {
    fn fmt_trait_proof<'a, C: AstFormatter + 'a>(
        &'a self,
        id: TraitClauseId,
        ctx: &'a C,
    ) -> impl Display + 'a {
        self.0.fmt_as_for_with(ctx, |ctx, trait_ref| {
            format!(
                "proof {}: ({}) = {}",
                id.format_as_implied(),
                trait_ref.trait_decl_ref.format_as_pred(ctx),
                trait_ref.with_ctx(ctx),
            )
        })
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Attribute {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let mut attr = String::new();
        self.fmt_unindented(ctx, &mut attr)?;
        let sep = format!("\n{}", ctx.indent());
        write!(f, "{}", attr.lines().format(sep.as_str()))
    }
}

impl Attribute {
    fn fmt_unindented<C: AstFormatter>(&self, ctx: &C, f: &mut impl fmt::Write) -> fmt::Result {
        match self {
            Attribute::Opaque => write!(f, "#[charon::opaque]"),
            Attribute::Exclude => write!(f, "#[charon::exclude]"),
            Attribute::Rename(name) => write!(f, "#[charon::rename(\"{name}\")]"),
            Attribute::VariantsPrefix(prefix) => {
                write!(f, "#[charon::variants_prefix(\"{prefix}\")]")
            }
            Attribute::VariantsSuffix(suffix) => {
                write!(f, "#[charon::variants_suffix(\"{suffix}\")]")
            }
            Attribute::Transparent => write!(f, "#[charon::transparent]"),
            Attribute::IsContract { kind, target } => {
                let target = target.with_ctx(ctx).to_string();
                write!(f, "#[charon::contract(kind = {kind:?}, for = {target:?})]")
            }
            Attribute::HasContract { kind, contract } => {
                let contract = ItemId::Fun(*contract);
                write!(
                    f,
                    "#[charon::has_contract(kind = {kind:?}, contract = {})]",
                    contract.with_ctx(ctx)
                )
            }
            Attribute::DocComment(comment) => {
                write!(
                    f,
                    "{}",
                    comment
                        .lines()
                        .map(|line| format!("///{line}"))
                        .format("\n")
                )
            }
            Attribute::Builtin(kind) => write!(f, "#[{kind}]"),
            Attribute::Unknown(attr) => write!(f, "#[{attr}]"),
        }
    }
}

/// Print a built-in attribute the way it is written in the source.
impl Display for from_rustc::AttributeKind {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        use from_rustc::AttributeKind;
        match self {
            AttributeKind::AutomaticallyDerived => write!(f, "automatically_derived"),
            AttributeKind::Cold => write!(f, "cold"),
            AttributeKind::Deprecated { deprecation, .. } => {
                write!(f, "deprecated")?;
                let since = match &deprecation.since {
                    from_rustc::DeprecatedSince::RustcVersion(v) => {
                        Some(format!("{}.{}.{}", v.major, v.minor, v.patch))
                    }
                    from_rustc::DeprecatedSince::Future => Some("future".to_owned()),
                    from_rustc::DeprecatedSince::NonStandard(since) => Some(since.to_string()),
                    from_rustc::DeprecatedSince::Unspecified | from_rustc::DeprecatedSince::Err => {
                        None
                    }
                };
                let since = since.map(|since| format!("since = \"{since}\""));
                let note = deprecation
                    .note
                    .as_ref()
                    .map(|note| format!("note = \"{}\"", note.name));
                let args = since.into_iter().chain(note).format(", ").to_string();
                if !args.is_empty() {
                    write!(f, "({args})")?;
                }
                Ok(())
            }
            AttributeKind::ExportName { name, .. } => write!(f, "export_name = \"{name}\""),
            AttributeKind::Fundamental => write!(f, "fundamental"),
            AttributeKind::Ignore { reason, .. } => {
                write!(f, "ignore")?;
                if let Some(reason) = reason {
                    write!(f, " = \"{reason}\"")?;
                }
                Ok(())
            }
            AttributeKind::Inline(inline, _) => match inline {
                from_rustc::InlineAttr::None => write!(f, "inline"),
                from_rustc::InlineAttr::Hint => write!(f, "inline(hint)"),
                from_rustc::InlineAttr::Always => write!(f, "inline(always)"),
                from_rustc::InlineAttr::Never => write!(f, "inline(never)"),
                from_rustc::InlineAttr::Force { .. } => write!(f, "rustc_force_inline"),
            },
            AttributeKind::LinkSection { name } => write!(f, "link_section = \"{name}\""),
            AttributeKind::Linkage(linkage, _) => {
                let linkage = match linkage {
                    from_rustc::Linkage::AvailableExternally => "available_externally",
                    from_rustc::Linkage::Common => "common",
                    from_rustc::Linkage::ExternalWeak => "extern_weak",
                    from_rustc::Linkage::External => "external",
                    from_rustc::Linkage::Internal => "internal",
                    from_rustc::Linkage::LinkOnceAny => "linkonce",
                    from_rustc::Linkage::LinkOnceODR => "linkonce_odr",
                    from_rustc::Linkage::WeakAny => "weak",
                    from_rustc::Linkage::WeakODR => "weak_odr",
                };
                write!(f, "linkage = \"{linkage}\"")
            }
            AttributeKind::MayDangle(_) => write!(f, "may_dangle"),
            AttributeKind::Naked(_) => write!(f, "naked"),
            AttributeKind::NoLink => write!(f, "no_link"),
            AttributeKind::NoMangle(_) => write!(f, "no_mangle"),
            AttributeKind::NonExhaustive(_) => write!(f, "non_exhaustive"),
            AttributeKind::Optimize(optimize, _) => match optimize {
                from_rustc::OptimizeAttr::Default => write!(f, "optimize(default)"),
                from_rustc::OptimizeAttr::DoNotOptimize => write!(f, "optimize(none)"),
                from_rustc::OptimizeAttr::Speed => write!(f, "optimize(speed)"),
                from_rustc::OptimizeAttr::Size => write!(f, "optimize(size)"),
            },
            AttributeKind::RustcAlign { align, .. } => write!(f, "rustc_align({align})"),
            AttributeKind::RustcIntrinsic => write!(f, "rustc_intrinsic"),
            AttributeKind::ShouldPanic { reason } => {
                write!(f, "should_panic")?;
                if let Some(reason) = reason {
                    write!(f, "(expected = \"{reason}\")")?;
                }
                Ok(())
            }
            AttributeKind::TargetFeature {
                features,
                was_forced,
                ..
            } => {
                let features = features.iter().map(|(feature, _)| feature).format(",");
                match was_forced {
                    false => write!(f, "target_feature(enable = \"{features}\")"),
                    true => write!(f, "target_feature(force = \"{features}\")"),
                }
            }
            AttributeKind::TrackCaller(_) => write!(f, "track_caller"),
        }
    }
}

impl Display for RawAttribute {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        write!(f, "{}", self.path)?;
        if let Some(args) = &self.args {
            write!(f, "({args})")?;
        }
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Byte {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Byte::Value(x) => write!(f, "{:#04x}", x),
            Byte::Uninit => write!(f, "--"),
            Byte::Provenance(p, ofs, i) => {
                write!(f, "&{}", p.with_ctx(ctx))?;
                if ofs.to_bits() != 0 {
                    write!(f, "+{}", ofs.to_bits())?;
                }
                write!(f, "[{i}]")
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for GlobalProvenance {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            GlobalProvenance::Global(g) => g.fmt_with_ctx(ctx, f),
            GlobalProvenance::Function(func, _) => func.fmt_with_ctx(ctx, f),
            GlobalProvenance::TypeId(ty) => write!(f, "TypeId({})", ty.with_ctx(ctx)),
        }
    }
}

impl ConstantExpr {
    fn format_as_match_pattern<'a, C: AstFormatter + 'a>(
        &'a self,
        ctx: &'a C,
    ) -> impl Display + 'a {
        std::fmt::from_fn(move |f| match self.kind() {
            ConstantExprKind::Discriminant(type_ref, variant_id) => {
                ctx.format_enum_variant(f, type_ref.id, *variant_id)
            }
            _ => self.fmt_with_ctx(ctx, f),
        })
    }
}

impl_display_via_ctx!(ConstantExpr);
impl<C: AstFormatter> FmtWithCtx<C> for ConstantExpr {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self.kind() {
            ConstantExprKind::Integer(v) => write!(f, "{v}"),
            ConstantExprKind::Float(v) => write!(f, "{v}"),
            ConstantExprKind::Bool(v) => write!(f, "{v}"),
            ConstantExprKind::Char(v) => write!(f, "'{}'", v.escape_debug()),
            ConstantExprKind::Str(v) => {
                write!(f, "\"{}\"", v.replace("\\", "\\\\").replace("\n", "\\n"))
            }
            ConstantExprKind::ByteStr(v) => write!(f, "{v:?}"),
            ConstantExprKind::Adt(variant_id, values) => {
                let ty_ref = self.ty().as_adt().unwrap();
                if ty_ref.is_tuple() {
                    let trailing_comma = if values.len() == 1 { "," } else { "" };
                    let values = values.iter().map(|v| v.with_ctx(ctx)).format(", ");
                    write!(f, "({values}{trailing_comma})")
                } else {
                    match variant_id {
                        None => ty_ref.id.fmt_with_ctx(ctx, f)?,
                        Some(variant_id) => ctx.format_enum_variant(f, ty_ref.id, *variant_id)?,
                    }
                    write!(f, " {{ ")?;
                    for (comma, (field_id, val)) in
                        repeat_except_first(", ").zip(values.iter_enumerated())
                    {
                        write!(f, "{}", comma.unwrap_or_default())?;
                        ctx.format_field_name(f, ty_ref.id, *variant_id, field_id)?;
                        write!(f, ": {}", val.with_ctx(ctx))?;
                    }
                    write!(f, " }}")
                }
            }
            ConstantExprKind::Array(values) => {
                let values = values.iter().map(|v| v.with_ctx(ctx)).format(", ");
                write!(f, "[{}]", values)
            }
            ConstantExprKind::Global(global_ref) => {
                write!(f, "{}", global_ref.with_ctx(ctx))
            }
            ConstantExprKind::TraitConst(trait_ref, const_id) => {
                write!(f, "{}::", trait_ref.with_ctx(ctx),)?;
                ctx.format_assoc_const_name(f, trait_ref.trait_id(), *const_id)?;
                Ok(())
            }
            ConstantExprKind::VTableRef(trait_ref) => {
                write!(f, "&vtable_of({})", trait_ref.with_ctx(ctx),)
            }
            ConstantExprKind::Discriminant(type_ref, variant_id) => {
                write!(f, "discriminant_of(")?;
                ctx.format_enum_variant(f, type_ref.id, *variant_id)?;
                write!(f, ")")
            }
            ConstantExprKind::Ref(cv, meta) => {
                if let Some(meta) = meta {
                    write!(
                        f,
                        "&{} with_metadata({})",
                        cv.with_ctx(ctx),
                        meta.with_ctx(ctx)
                    )
                } else {
                    write!(f, "&{}", cv.with_ctx(ctx))
                }
            }
            ConstantExprKind::Ptr(rk, cv, meta) => {
                let rk = match rk {
                    RefKind::Mut => "&raw mut",
                    RefKind::Shared => "&raw const",
                };
                if let Some(meta) = meta {
                    write!(
                        f,
                        "{} {} with_metadata({})",
                        rk,
                        cv.with_ctx(ctx),
                        meta.with_ctx(ctx)
                    )
                } else {
                    write!(f, "{} {}", rk, cv.with_ctx(ctx))
                }
            }
            ConstantExprKind::Var(id) => write!(f, "{}", id.with_ctx(ctx)),
            ConstantExprKind::Call(fp, args) => {
                let args = args.iter().map(|arg| arg.with_ctx(ctx)).format(", ");
                write!(f, "{}({args})", fp.with_ctx(ctx))
            }
            ConstantExprKind::FnDef(fp) => {
                write!(f, "{}", fp.with_ctx(ctx))
            }
            ConstantExprKind::FnPtr(fp) => {
                write!(f, "fnptr({})", fp.with_ctx(ctx))
            }
            ConstantExprKind::Cast(value, kind) => {
                write!(f, "{}({})", kind.with_ctx(ctx), value.with_ctx(ctx))
            }
            ConstantExprKind::TypeId(ty) => {
                write!(f, "TypeId({})", ty.with_ctx(ctx))
            }
            ConstantExprKind::SizeOf(ty) => {
                write!(f, "size_of::<{}>()", ty.with_ctx(ctx))
            }
            ConstantExprKind::AlignOf(ty) => {
                write!(f, "align_of::<{}>()", ty.with_ctx(ctx))
            }
            &ConstantExprKind::OffsetOf(ref ty, variant, field) => {
                write!(f, "offset_of({}.", ty.with_ctx(ctx))?;
                if let Some(variant) = variant {
                    ctx.format_enum_variant_name(f, ty.id, variant)?;
                    write!(f, ".")?;
                }
                ctx.format_field_name(f, ty.id, variant, field)?;
                write!(f, ")")
            }
            ConstantExprKind::PtrNoProvenance(v) => write!(f, "no-provenance {v}"),
            ConstantExprKind::ExternSymbol(name) => write!(f, "&raw const <extern:{name}>"),
            ConstantExprKind::RawMemory(bytes) => {
                let bytes = bytes.iter().map(|v| v.with_ctx(ctx)).format(", ");
                write!(f, "RawMemory({})", bytes)
            }
            ConstantExprKind::Opaque(cause) => write!(f, "Opaque({cause})"),
        }
    }
}

impl Display for ReprOptions {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let algorithm = match self.repr_algo {
            ReprAlgorithm::Rust => "Rust",
            ReprAlgorithm::C => "C",
        };
        write!(f, "repr({algorithm}")?;
        if let Some(modifier) = &self.align_modif {
            match modifier {
                AlignmentModifier::Align(align) => write!(f, ", align({align})")?,
                AlignmentModifier::Pack(pack) => write!(f, ", packed({pack})")?,
            }
        }
        if self.transparent {
            write!(f, ", transparent")?;
        }
        if let Some(int_ty) = self.explicit_discr_type {
            write!(f, ", discriminant {int_ty}")?;
        }
        write!(f, ")")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Size {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match &self.chosen {
            Some(chosen) => write!(f, "{}", chosen.with_ctx(ctx))?,
            None => write!(f, "?")?,
        }
        if let Some(guarantee) = &self.guarantee {
            write!(f, " (guaranteed: {})", guarantee.with_ctx(ctx))?;
        }
        Ok(())
    }
}

impl_display_via_ctx!(SizeExpr);
impl<C: AstFormatter> FmtWithCtx<C> for SizeExpr {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self.kind() {
            SizeExprKind::Constant(constant) => write!(f, "{}", constant.with_ctx(ctx)),
            SizeExprKind::FromMetadata(metadata) => write!(f, "{metadata}"),
            SizeExprKind::Max(values) => write!(
                f,
                "max({})",
                values.iter().map(|value| value.with_ctx(ctx)).format(", ")
            ),
            SizeExprKind::Min(values) => write!(
                f,
                "min({})",
                values.iter().map(|value| value.with_ctx(ctx)).format(", ")
            ),
            SizeExprKind::Plus(left, right) => {
                write!(f, "({} + {})", left.with_ctx(ctx), right.with_ctx(ctx))
            }
            SizeExprKind::Scale(base, multiplier) => {
                write!(f, "({} * {})", base.with_ctx(ctx), multiplier.with_ctx(ctx))
            }
            SizeExprKind::AtLeast(value) => write!(f, "at_least({})", value.with_ctx(ctx)),
            SizeExprKind::AlignTo { base, target_align } => write!(
                f,
                "align_to({}, {})",
                base.with_ctx(ctx),
                target_align.with_ctx(ctx)
            ),
            SizeExprKind::IfInhabited {
                ty,
                then_size,
                else_size,
            } => write!(
                f,
                "if_inhabited({}, {}, {})",
                ty.with_ctx(ctx),
                then_size.with_ctx(ctx),
                else_size.with_ctx(ctx)
            ),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Region {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Region::Static => write!(f, "'static"),
            Region::Var(var) => write!(f, "{}", var.with_ctx(ctx)),
            Region::Body(id) => write!(f, "'{}", id),
            Region::Erased => write!(f, "'_"),
        }
    }
}

impl<T> RegionBinder<T> {
    fn fmt_params_with_ctx<C: AstFormatter>(&self, ctx: &C) -> String {
        let mut params = self
            .regions
            .iter()
            .map(|r| r.with_ctx(ctx))
            .format(", ")
            .to_string();
        let predicates = self
            .types_outlive
            .iter()
            .map(|pred| pred.fmt_as_for(ctx))
            .chain(self.regions_outlive.iter().map(|pred| pred.fmt_as_for(ctx)))
            .format(", ")
            .to_string();
        if !predicates.is_empty() {
            if !params.is_empty() {
                params.push(' ');
            }
            params.push_str("where ");
            params.push_str(&predicates);
        }
        params
    }

    /// Format the parameters and contents of this binder and returns the resulting strings.
    fn fmt_split<'a, C>(&'a self, ctx: &'a C) -> (String, String)
    where
        C: AstFormatter,
        T: FmtWithCtx<C::Reborrow<'a>>,
    {
        self.fmt_split_with(ctx, |ctx, x| x.to_string_with_ctx(ctx))
    }
    /// Format the parameters and contents of this binder and returns the resulting strings.
    fn fmt_split_with<'a, C>(
        &'a self,
        ctx: &'a C,
        fmt_inner: impl FnOnce(&C::Reborrow<'a>, &T) -> String,
    ) -> (String, String)
    where
        C: AstFormatter,
    {
        let ctx = &ctx.push_bound_regions(&self.regions);
        (
            self.fmt_params_with_ctx(ctx),
            fmt_inner(ctx, &self.skip_binder),
        )
    }

    /// Formats the binder as `for<params> value`.
    fn fmt_as_for<'a, C>(&'a self, ctx: &'a C) -> String
    where
        C: AstFormatter,
        T: FmtWithCtx<C::Reborrow<'a>>,
    {
        self.fmt_as_for_with(ctx, |ctx, x| x.to_string_with_ctx(ctx))
    }
    /// Formats the binder as `for<params> value`.
    fn fmt_as_for_with<'a, C>(
        &'a self,
        ctx: &'a C,
        fmt_inner: impl FnOnce(&C::Reborrow<'a>, &T) -> String,
    ) -> String
    where
        C: AstFormatter,
        T: FmtWithCtx<C::Reborrow<'a>>,
    {
        let (regions, value) = self.fmt_split_with(ctx, fmt_inner);
        let regions = if regions.is_empty() {
            "".to_string()
        } else {
            format!("for<{regions}> ",)
        };
        format!("{regions}{value}",)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for RegionDbVar {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ctx.format_bound_var(f, *self, "'_", |v| {
            v.name.as_ref().map(|name| name.to_string())
        })
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for RegionParam {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if self.mutability.is_mutable() {
            write!(f, "mut ")?;
        }
        match &self.name {
            Some(name) => write!(f, "{name}"),
            None => {
                write!(f, "'_{}", self.index)?;
                if let Some(d @ 1..) = ctx.binder_depth().checked_sub(1) {
                    write!(f, "_{d}")?;
                }
                Ok(())
            }
        }
    }
}

impl_display_via_ctx!(Rvalue);
impl<C: AstFormatter> FmtWithCtx<C> for Rvalue {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Rvalue::Use(x, retag) => {
                if let WithRetag::No = retag {
                    write!(f, "noretag ")?;
                }
                write!(f, "{}", x.with_ctx(ctx))
            }
            Rvalue::Ref {
                place,
                kind: borrow_kind,
                ptr_metadata,
            } => {
                let borrow_kind = match borrow_kind {
                    BorrowKind::Shared => "&",
                    BorrowKind::Mut => "&mut ",
                    BorrowKind::TwoPhaseMut => "&two-phase-mut ",
                    BorrowKind::UniqueImmutable => "&uniq ",
                    BorrowKind::Shallow => "&shallow ",
                };
                if ptr_metadata.ty().is_unit() {
                    // Hide unit metadata
                    write!(f, "{borrow_kind}{}", place.with_ctx(ctx))?;
                } else {
                    write!(
                        f,
                        "{borrow_kind}{} with_metadata({})",
                        place.with_ctx(ctx),
                        ptr_metadata.with_ctx(ctx)
                    )?;
                }
                Ok(())
            }
            Rvalue::RawPtr {
                place,
                kind: mutability,
                ptr_metadata,
            } => {
                let ptr_kind = match mutability {
                    RefKind::Shared => "&raw const ",
                    RefKind::Mut => "&raw mut ",
                };
                if ptr_metadata.ty().is_unit() {
                    // Hide unit metadata
                    write!(f, "{ptr_kind}{}", place.with_ctx(ctx))?;
                } else {
                    write!(
                        f,
                        "{ptr_kind}{} with_metadata({})",
                        place.with_ctx(ctx),
                        ptr_metadata.with_ctx(ctx)
                    )?;
                }
                Ok(())
            }

            Rvalue::BinaryOp(binop, x, y) => {
                write!(f, "{} {} {}", x.with_ctx(ctx), binop, y.with_ctx(ctx))
            }
            Rvalue::UnaryOp(unop, x) => {
                write!(f, "{}({})", unop.with_ctx(ctx), x.with_ctx(ctx))
            }
            Rvalue::NullaryOp(op) => op.fmt_with_ctx(ctx, f),
            Rvalue::Discriminant(p) => {
                write!(f, "@discriminant({})", p.with_ctx(ctx),)
            }
            Rvalue::Aggregate(kind, ops) => {
                let ops_s = ops.iter().map(|op| op.with_ctx(ctx)).format(", ");
                match kind {
                    AggregateKind::Adt(ty_ref, variant_id, field_id) => {
                        if ty_ref.is_tuple() {
                            let trailing_comma = if ops.len() == 1 { "," } else { "" };
                            write!(f, "({ops_s}{trailing_comma})")
                        } else {
                            match variant_id {
                                None => ty_ref.id.fmt_with_ctx(ctx, f)?,
                                Some(variant_id) => {
                                    ctx.format_enum_variant(f, ty_ref.id, *variant_id)?
                                }
                            }
                            write!(f, " {{ ")?;
                            for (comma, (i, op)) in
                                repeat_except_first(", ").zip(ops.iter().enumerate())
                            {
                                write!(f, "{}", comma.unwrap_or_default())?;
                                let field_id = match *field_id {
                                    None => FieldId::new(i),
                                    Some(field_id) => {
                                        assert_eq!(i, 0); // there should be only one operand
                                        field_id
                                    }
                                };
                                ctx.format_field_name(f, ty_ref.id, *variant_id, field_id)?;
                                write!(f, ": {}", op.with_ctx(ctx))?;
                            }
                            write!(f, " }}")
                        }
                    }
                    AggregateKind::Array(..) => {
                        write!(f, "[{}]", ops_s)
                    }
                    AggregateKind::RawPtr(_, rmut) => {
                        let mutability = match rmut {
                            RefKind::Shared => "const",
                            RefKind::Mut => "mut ",
                        };
                        write!(f, "*{} ({})", mutability, ops_s)
                    }
                }
            }
            Rvalue::Len(place, ..) => write!(f, "len({})", place.with_ctx(ctx)),
            Rvalue::Repeat(operand, _, len, _) => {
                write!(f, "[{}; {}]", operand.with_ctx(ctx), len.with_ctx(ctx))
            }
        }
    }
}

impl Display for IntegerValue {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        match self {
            IntegerValue::Signed(ty, v) => write!(f, "{v}{ty}"),
            IntegerValue::Unsigned(ty, v) => write!(f, "{v}{ty}"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for BorrowckStatement {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            BorrowckStatement::FakeRead(place) => {
                write!(f, "fake_read({})", place.with_ctx(ctx))
            }
            BorrowckStatement::SetType {
                place,
                ty,
                variance,
            } => {
                let relation = match variance {
                    Variance::Covariant => "<=",
                    Variance::Contravariant => ">=",
                    Variance::Invariant => "==",
                    Variance::Bivariant => panic!("bivariant SetType statement"),
                    Variance::Unknown => panic!("SetType statement with unknown variance"),
                };
                write!(
                    f,
                    "set_type(typeof({}) {relation} {})",
                    place.with_ctx(ctx),
                    ty.with_ctx(ctx)
                )
            }
            BorrowckStatement::SetOutlives(ty, region) => write!(
                f,
                "set_outlives({}, {})",
                ty.with_ctx(ctx),
                region.with_ctx(ctx)
            ),
            BorrowckStatement::PredicateHolds(predicate) => {
                write!(f, "predicate_holds({})", predicate.with_ctx(ctx))
            }
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for ullbc::Statement {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let tab = ctx.indent();
        use ullbc::StatementKind;
        if ctx.hide_storage_statements()
            && (self.kind.is_storage_live() || self.kind.is_storage_dead())
        {
            return Ok(());
        }
        for line in &self.comments_before {
            writeln!(f, "{tab}// {line}")?;
        }
        fmt_safety_comment(ctx, f, self)?;
        match &self.kind {
            StatementKind::Assign(place, rvalue) => {
                write!(f, "{tab}{} = {}", place.with_ctx(ctx), rvalue.with_ctx(ctx),)
            }
            StatementKind::Borrowck(statement) => {
                write!(f, "{tab}{}", statement.with_ctx(ctx))
            }
            StatementKind::SetDiscriminant(place, variant_id) => write!(
                f,
                "{tab}@discriminant({}) = {}",
                place.with_ctx(ctx),
                variant_id
            ),
            StatementKind::StorageLive(var_id) => {
                write!(f, "{tab}storage_live({})", var_id.with_ctx(ctx))
            }
            StatementKind::StorageDead(var_id) => {
                write!(f, "{tab}storage_dead({})", var_id.with_ctx(ctx))
            }
            StatementKind::PlaceMention(place) => {
                write!(f, "{tab}_ = {}", place.with_ctx(ctx))
            }
            StatementKind::Assert { assert, on_failure } => {
                write!(
                    f,
                    "{tab}{} else {}",
                    assert.with_ctx(ctx),
                    on_failure.with_ctx(ctx)
                )
            }
            StatementKind::Nop => write!(f, "{tab}nop"),
        }?;
        writeln!(f, ";")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for llbc::Statement {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let tab = ctx.indent();
        use llbc::StatementKind;
        if ctx.hide_storage_statements()
            && (self.kind.is_storage_live() || self.kind.is_storage_dead())
        {
            return Ok(());
        }
        for line in &self.comments_before {
            writeln!(f, "{tab}// {line}")?;
        }
        if self.kind.is_nop() {
            return Ok(());
        }
        fmt_safety_comment(ctx, f, self)?;
        write!(f, "{tab}")?;
        match &self.kind {
            StatementKind::Assign(place, rvalue) => {
                write!(f, "{} = {}", place.with_ctx(ctx), rvalue.with_ctx(ctx),)
            }
            StatementKind::Borrowck(statement) => write!(f, "{}", statement.with_ctx(ctx)),
            StatementKind::SetDiscriminant(place, variant_id) => {
                write!(f, "@discriminant({}) = {}", place.with_ctx(ctx), variant_id)
            }
            StatementKind::StorageLive(var_id) => {
                write!(f, "storage_live({})", var_id.with_ctx(ctx))
            }
            StatementKind::StorageDead(var_id) => {
                write!(f, "storage_dead({})", var_id.with_ctx(ctx))
            }
            StatementKind::PlaceMention(place) => {
                write!(f, "_ = {}", place.with_ctx(ctx))
            }
            StatementKind::Drop {
                place,
                fn_ptr,
                kind,
                on_unwind,
            } => {
                let kind = match kind {
                    DropKind::Precise => "drop",
                    DropKind::Conditional => "conditional_drop",
                };
                write!(
                    f,
                    "{kind}[{}] {}",
                    fn_ptr.with_ctx(ctx),
                    place.with_ctx(ctx),
                )?;
                fmt_llbc_unwind_block(ctx, f, on_unwind)
            }
            StatementKind::Assert {
                assert,
                on_failure,
                on_unwind,
            } => {
                write!(
                    f,
                    "{} else {}",
                    assert.with_ctx(ctx),
                    on_failure.with_ctx(ctx)
                )?;
                fmt_llbc_unwind_block(ctx, f, on_unwind)
            }
            StatementKind::InlineAsm {
                asm,
                fallthrough,
                labels,
                on_unwind,
            } => {
                write!(f, "{}", asm.with_ctx(ctx))?;
                if fallthrough.is_some() || !labels.is_empty() {
                    write!(f, " {{")?;
                    let ctx1 = &ctx.increase_indent();
                    if let Some(target) = fallthrough {
                        let tab = ctx1.indent();
                        let ctx = &ctx1.increase_indent();
                        write!(
                            f,
                            "\n{tab}fallthrough => {{\n{}{tab}}}",
                            target.with_ctx(ctx)
                        )?;
                    }
                    for (branch, target) in labels.iter_enumerated() {
                        let tab = ctx1.indent();
                        let ctx = &ctx1.increase_indent();
                        write!(
                            f,
                            "\n{tab}label {} => {{\n{}{tab}}}",
                            branch.index(),
                            target.with_ctx(ctx)
                        )?;
                    }
                    write!(f, "\n{tab}}}")?;
                }
                fmt_llbc_unwind_block(ctx, f, on_unwind)?;
                Ok(())
            }
            StatementKind::Call { call, on_unwind } => {
                write!(f, "{}", call.with_ctx(ctx))?;
                fmt_llbc_unwind_block(ctx, f, on_unwind)
            }
            StatementKind::Panic { name, on_unwind } => {
                write!(f, "{}", AbortKind::Panic(Some(name.clone())).with_ctx(ctx))?;
                fmt_llbc_unwind_block(ctx, f, on_unwind)
            }
            StatementKind::UndefinedBehavior => {
                write!(f, "{}", AbortKind::UndefinedBehavior.with_ctx(ctx))
            }
            StatementKind::UnwindTerminate => {
                write!(f, "{}", AbortKind::UnwindTerminate.with_ctx(ctx))
            }
            StatementKind::Return => write!(f, "return"),
            StatementKind::UnwindResume => write!(f, "unwind_continue"),
            StatementKind::Break(index) => write!(f, "break {index}"),
            StatementKind::Continue(index) => write!(f, "continue {index}"),
            StatementKind::Switch { data, branches } => match &data.scrutinee {
                SwitchScrutinee::Value(discr)
                    if let Some((then_branch, else_branch)) = data.as_if() =>
                {
                    let true_st = &branches[then_branch];
                    let false_st = &branches[else_branch];
                    let ctx = &ctx.increase_indent();
                    write!(
                        f,
                        "if {} {{\n{}{tab}}} else {{\n{}{tab}}}",
                        discr.with_ctx(ctx),
                        true_st.with_ctx(ctx),
                        false_st.with_ctx(ctx),
                    )
                }
                SwitchScrutinee::Value(discr) => {
                    writeln!(f, "switch {} {{", discr.with_ctx(ctx))?;
                    let ctx1 = &ctx.increase_indent();
                    let inner_tab1 = ctx1.indent();
                    let ctx2 = &ctx1.increase_indent();
                    let cases_by_branch = data.group_by_branch();
                    for (branch_id, st) in branches.iter_enumerated() {
                        let cases = &cases_by_branch[branch_id];
                        let cases = if cases.is_empty() && data.fallback != Some(branch_id) {
                            "_".to_owned()
                        } else {
                            cases
                                .iter()
                                .map(|value| value.to_string_with_ctx(ctx))
                                .chain((data.fallback == Some(branch_id)).then_some("_".to_owned()))
                                .format(" | ")
                                .to_string()
                        };
                        writeln!(
                            f,
                            "{inner_tab1}{} => {{\n{}{inner_tab1}}},",
                            cases,
                            st.with_ctx(ctx2),
                        )?;
                    }
                    write!(f, "{tab}}}")
                }
                SwitchScrutinee::Discriminant(discr) => {
                    writeln!(f, "match {} {{", discr.with_ctx(ctx))?;
                    let ctx1 = &ctx.increase_indent();
                    let inner_tab1 = ctx1.indent();
                    let ctx2 = &ctx1.increase_indent();
                    let cases_by_branch = data.group_by_branch();
                    for (branch_id, st) in branches.iter_enumerated() {
                        let cases = &cases_by_branch[branch_id];
                        let cases = if cases.is_empty() && data.fallback != Some(branch_id) {
                            "_".to_owned()
                        } else {
                            cases
                                .iter()
                                .map(|value| value.format_as_match_pattern(ctx).to_string())
                                .chain((data.fallback == Some(branch_id)).then_some("_".to_owned()))
                                .format(" | ")
                                .to_string()
                        };
                        writeln!(
                            f,
                            "{inner_tab1}{cases} => {{\n{}{inner_tab1}}},",
                            st.with_ctx(ctx2),
                        )?;
                    }
                    write!(f, "{tab}}}")
                }
            },
            StatementKind::Loop(body) => {
                let ctx = &ctx.increase_indent();
                write!(f, "loop {{\n{}{tab}}}", body.with_ctx(ctx))
            }
            StatementKind::Nop => unreachable!(),
        }?;
        writeln!(f)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for SwitchScrutinee {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            SwitchScrutinee::Value(operand) => operand.fmt_with_ctx(ctx, f),
            SwitchScrutinee::Discriminant(place) => place.fmt_with_ctx(ctx, f),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Terminator {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let tab = ctx.indent();
        for line in &self.comments_before {
            writeln!(f, "{tab}// {line}")?;
        }
        fmt_safety_comment(ctx, f, self)?;
        write!(f, "{tab}")?;
        match &self.kind {
            TerminatorKind::Goto { target } => write!(f, "goto bb{target}"),
            TerminatorKind::Switch { data, branches } => {
                if let Some((then_branch, else_branch)) = data.as_if() {
                    let true_block = branches[then_branch];
                    let false_block = branches[else_branch];
                    write!(
                        f,
                        "if {} -> bb{} else -> bb{}",
                        data.scrutinee.with_ctx(ctx),
                        true_block,
                        false_block
                    )
                } else {
                    let maps = data
                        .branches
                        .iter()
                        .map(|(value, branch_id)| {
                            format!(
                                "{}: bb{}",
                                value.format_as_match_pattern(ctx),
                                branches[*branch_id]
                            )
                        })
                        .chain(
                            data.fallback
                                .map(|branch_id| format!("otherwise: bb{}", branches[branch_id])),
                        )
                        .format(", ");
                    match &data.scrutinee {
                        SwitchScrutinee::Value(discr) => {
                            write!(f, "switch {} -> {}", discr.with_ctx(ctx), maps)
                        }
                        SwitchScrutinee::Discriminant(place) => {
                            write!(f, "match {} -> {}", place.with_ctx(ctx), maps)
                        }
                    }
                }
            }
            TerminatorKind::Call {
                call,
                target,
                on_unwind,
            } => {
                let call = call.with_ctx(ctx);
                write!(f, "{call} -> bb{target} (unwind: bb{on_unwind})",)
            }
            TerminatorKind::Drop {
                kind,
                place,
                fn_ptr,
                target,
                on_unwind,
            } => {
                let kind = match kind {
                    DropKind::Precise => "drop",
                    DropKind::Conditional => "conditional_drop",
                };
                write!(
                    f,
                    "{kind}[{}] {} -> bb{target} (unwind: bb{on_unwind})",
                    fn_ptr.with_ctx(ctx),
                    place.with_ctx(ctx),
                )
            }
            TerminatorKind::Assert {
                assert,
                target,
                on_unwind,
            } => {
                write!(
                    f,
                    "assert {} -> bb{target} (unwind: bb{on_unwind})",
                    assert.with_ctx(ctx),
                )
            }
            TerminatorKind::InlineAsm {
                asm,
                fallthrough,
                labels,
                on_unwind,
            } => {
                let targets =
                    fallthrough
                        .iter()
                        .map(|target| format!("fallthrough: bb{target}"))
                        .chain(labels.iter_enumerated().map(|(branch, target)| {
                            format!("label {}: bb{target}", branch.index())
                        }))
                        .chain([format!("unwind: bb{on_unwind}")])
                        .format(", ");
                write!(f, "{} -> {targets}", asm.with_ctx(ctx))
            }
            TerminatorKind::Panic { name, on_unwind } => write!(
                f,
                "{} -> (unwind: bb{on_unwind})",
                AbortKind::Panic(Some(name.clone())).with_ctx(ctx)
            ),
            TerminatorKind::UndefinedBehavior => {
                write!(f, "{}", AbortKind::UndefinedBehavior.with_ctx(ctx))
            }
            TerminatorKind::UnwindTerminate => {
                write!(f, "{}", AbortKind::UnwindTerminate.with_ctx(ctx))
            }
            TerminatorKind::Return => write!(f, "return"),
            TerminatorKind::UnwindResume => write!(f, "unwind_continue"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitParam {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.clause_id.format_as_required())?;
        if let Some(d @ 1..) = ctx.binder_depth().checked_sub(1) {
            write!(f, "_{d}")?;
        }
        write!(f, ": {}", self.trait_.format_as_pred(ctx))
    }
}

impl TraitClauseId {
    pub(crate) fn format_as_implied(self) -> impl Display {
        std::fmt::from_fn(move |f| write!(f, "ImpliedClause{self}"))
    }

    pub(crate) fn format_as_required(self) -> impl Display {
        std::fmt::from_fn(move |f| write!(f, "TraitClause{self}"))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitDecl {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Update the context
        let ctx = &ctx.set_generics(&self.generics);

        let keyword = if self.is_unsafe {
            "unsafe trait"
        } else {
            "trait"
        };

        self.item_meta
            .fmt_item_intro(f, ctx, keyword, self.def_id)?;

        let (generics, clauses) = self.generics.fmt_with_ctx_with_trait_clauses(ctx);
        write!(f, "{generics}{clauses}")?;

        let any_item = !self.implied_clauses.is_empty()
            || !self.consts.is_empty()
            || !self.types.is_empty()
            || !self.methods.is_empty();
        if any_item {
            write!(f, "\n{{\n")?;
            for c in &self.implied_clauses {
                writeln!(
                    f,
                    "{TAB_INCR}proof {}: {}",
                    c.clause_id.format_as_implied(),
                    c.trait_.format_as_pred(ctx)
                )?
            }
            for assoc_const in &self.consts {
                let name = &assoc_const.name;
                let ty = assoc_const.ty.with_ctx(ctx);
                writeln!(f, "{TAB_INCR}const {name} : {ty}")?;
            }
            for assoc_ty in &self.types {
                let name = assoc_ty.name();
                let ctx = &ctx.push_binder(Cow::Borrowed(&assoc_ty.params));
                let clauses = assoc_ty
                    .params
                    .formatted_clauses(ctx)
                    .map(|x| x.to_string())
                    .chain(assoc_ty.skip_binder.implied_clauses.iter().map(|clause| {
                        format!(
                            "proof {}: {}",
                            clause.clause_id.format_as_implied(),
                            clause.trait_.format_as_pred(ctx)
                        )
                    }));
                let params = if assoc_ty.params.has_explicits() {
                    format!("<{}>", assoc_ty.params.formatted_params(ctx).format(", "))
                } else {
                    String::new()
                };
                write!(f, "{TAB_INCR}type {name}{params}")?;
                if let Some(default) = &assoc_ty.skip_binder.default {
                    write!(f, " = {}", default.value.with_ctx(ctx))?;
                }
                write!(f, "{}", fmt_where_clauses(clauses, TAB_INCR))?;
                writeln!(f)?;
            }
            for method in self.methods() {
                for attr in &method.skip_binder.item_meta.attr_info.attributes {
                    if !attr.is_doc_comment() {
                        writeln!(f, "{TAB_INCR}{}", attr.with_ctx(ctx))?;
                    }
                }
                let name = method.name();
                let (params, method) =
                    method.fmt_split_with(ctx, |ctx, method| match &method.default {
                        Some(fn_ref) => format!(" = {}", fn_ref.to_string_with_ctx(ctx)),
                        None => format!(";"),
                    });
                writeln!(f, "{TAB_INCR}fn {name}{params}{method}")?;
            }
            if let Some(vtb_ref) = &self.vtable {
                writeln!(f, "{TAB_INCR}vtable: {}", vtb_ref.with_ctx(ctx))?;
            } else {
                writeln!(f, "{TAB_INCR}non-dyn-compatible")?;
            }
            write!(f, "}}")?;
        }
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitDeclId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ItemId::from(*self).fmt_with_ctx(ctx, f)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitDeclRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let trait_id = self.id.with_ctx(ctx);
        let generics = self.generics.with_ctx(ctx);
        write!(f, "{trait_id}{generics}")
    }
}

impl TraitDeclRef {
    /// Split off the `Self` type. The returned `TraitDeclRef` has incorrect generics. The returned
    /// `Self` is `None` for monomorphized traits.
    pub fn split_self(&self) -> (Option<Ty>, Self) {
        let mut pred = self.clone();
        let self_ty = pred.generics.types.remove_and_shift_ids(TypeVarId::ZERO);
        (self_ty, pred)
    }

    fn format_as_pred<'a, C: AstFormatter + 'a>(&'a self, ctx: &'a C) -> impl Display + 'a {
        std::fmt::from_fn(move |f| {
            let (self_ty, pred) = self.split_self();
            match self_ty {
                Some(self_ty) => write!(f, "{}: {}", self_ty.with_ctx(ctx), pred.with_ctx(ctx)),
                // Monomorphized traits don't have self types.
                None => write!(f, "{}", pred.with_ctx(ctx)),
            }
        })
    }

    fn format_as_impl<'a, C: AstFormatter>(&'a self, ctx: &'a C) -> impl Display + 'a {
        std::fmt::from_fn(move |f| {
            let (self_ty, pred) = self.split_self();
            match self_ty {
                Some(self_ty) => write!(f, "{} for {}", pred.with_ctx(ctx), self_ty.with_ctx(ctx)),
                // Monomorphized traits don't have self types.
                None => write!(f, "{}", pred.with_ctx(ctx)),
            }
        })
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitImpl {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let trait_id = self.impl_trait.id;
        writeln!(f, "// Full name: {}", self.item_meta.name.full_name(ctx))?;
        if ctx.include_safety()
            && let Some(tr) = ctx.get_crate()
            && self.is_unsafe_to_declare(tr)
        {
            writeln!(f, "// unsafe to declare")?;
        }

        // Update the context
        let ctx = &ctx.set_generics(&self.generics);

        let (generics, clauses) = self.generics.fmt_with_ctx_with_trait_clauses(ctx);
        let impl_trait = self.impl_trait.format_as_impl(ctx);
        if self.is_unsafe {
            write!(f, "unsafe ")?;
        }
        write!(f, "impl{generics}")?;
        if let Some(short_name) = trait_impl_short_name(ctx, self.def_id) {
            write!(f, " \"{}\"", short_name.with_ctx(ctx))?;
        }
        let negative = if self.is_negative { "!" } else { "" };
        write!(f, " {negative}{impl_trait}{clauses}",)?;

        let newline = if clauses.is_empty() {
            " ".to_string()
        } else {
            "\n".to_string()
        };
        writeln!(f, "{newline}{{")?;

        let any_item = !self.implied_trait_refs.is_empty()
            || !self.consts.is_empty()
            || !self.types.is_empty()
            || !self.methods.is_empty();
        if any_item {
            for (id, trait_ref) in self.implied_trait_refs.iter_enumerated() {
                writeln!(f, "{TAB_INCR}{}", trait_ref.fmt_trait_proof(id, ctx))?;
            }
            for (const_id, global) in self.consts.iter_enumerated() {
                write!(f, "{TAB_INCR}const ")?;
                ctx.format_assoc_const_name(f, trait_id, const_id)?;
                writeln!(f, " = {}", global.with_ctx(ctx))?;
            }
            for (type_id, assoc_ty) in self.types.iter_enumerated() {
                let ctx = &ctx.push_binder(Cow::Borrowed(&assoc_ty.params));
                let params = if assoc_ty.params.has_explicits() {
                    format!("<{}>", assoc_ty.params.formatted_params(ctx).format(", "))
                } else {
                    String::new()
                };
                let ty = assoc_ty.skip_binder.value.with_ctx(ctx);
                let clauses = assoc_ty
                    .params
                    .formatted_clauses(ctx)
                    .map(|x| x.to_string())
                    .chain(
                        assoc_ty
                            .skip_binder
                            .implied_trait_refs
                            .iter_enumerated()
                            .map(|(id, trait_ref)| trait_ref.fmt_trait_proof(id, ctx).to_string()),
                    );
                write!(f, "{TAB_INCR}type ")?;
                ctx.format_assoc_type_name(f, trait_id, type_id)?;
                write!(f, "{params} = {ty}")?;
                write!(f, "{}", fmt_where_clauses(clauses, TAB_INCR))?;
                writeln!(f)?;
            }
            for (method_id, bound_fn) in self.methods.iter_enumerated() {
                let (params, fn_ref) = bound_fn.fmt_split(ctx);
                write!(f, "{TAB_INCR}fn ")?;
                ctx.format_method_name(f, trait_id, method_id)?;
                writeln!(f, "{params} = {fn_ref}")?;
            }
        }
        match &self.vtable {
            VTableDecl::VTable(vtb_ref) => {
                writeln!(f, "{TAB_INCR}vtable: {}", vtb_ref.with_ctx(ctx))?
            }
            VTableDecl::Lazy => writeln!(f, "{TAB_INCR}vtable: lazy")?,
            VTableDecl::Unknown(msg) => writeln!(f, "{TAB_INCR}vtable: unknown // {msg}")?,
            VTableDecl::NotDynCompatible => writeln!(f, "{TAB_INCR}non-dyn-compatible")?,
        }
        write!(f, "}}")?;
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitImplId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ItemId::from(*self).fmt_with_ctx(ctx, f)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitImplRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let id = self.id.with_ctx(ctx);
        let generics = self.generics.with_ctx(ctx);
        write!(f, "{id}{generics}")
    }
}

impl Display for TraitItemName {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> std::result::Result<(), fmt::Error> {
        write!(f, "{}", self.0)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match &self.kind {
            TraitRefKind::SelfId => write!(f, "Self"),
            TraitRefKind::ParentClause(sub, clause_id, args) => {
                let sub = sub.with_ctx(ctx);
                write!(
                    f,
                    "{sub}::{}{}",
                    clause_id.format_as_implied(),
                    args.with_ctx(ctx)
                )
            }
            TraitRefKind::ItemClause {
                trait_ref,
                type_id,
                generics,
                clause_id,
                clause_args,
            } => {
                write!(f, "{}::", trait_ref.with_ctx(ctx))?;
                ctx.format_assoc_type_name(f, trait_ref.trait_id(), *type_id)?;
                write!(
                    f,
                    "{}::{}{}",
                    generics.with_ctx(ctx),
                    clause_id.format_as_implied(),
                    clause_args.with_ctx(ctx),
                )
            }
            TraitRefKind::TraitImpl(impl_ref) => {
                write!(f, "{}", impl_ref.with_ctx(ctx))
            }
            TraitRefKind::Clause(id, args) => {
                write!(f, "{}{}", id.with_ctx(ctx), args.with_ctx(ctx))
            }
            TraitRefKind::BuiltinOrAuto { types, .. } => {
                let impl_trait = self.trait_decl_ref.format_as_impl(ctx);
                write!(f, "{{built_in impl {impl_trait}")?;
                if !types.is_empty() {
                    let trait_id = self.trait_decl_ref.id;
                    let types = types
                        .iter_indexed()
                        .map(|(type_id, assoc_ty)| {
                            std::fmt::from_fn(move |f| {
                                ctx.format_assoc_type_name(f, trait_id, type_id)?;
                                let ty = assoc_ty.value.with_ctx(ctx);
                                write!(f, "  = {ty}")
                            })
                        })
                        .join(", ");
                    write!(f, " where {types}")?;
                }
                write!(f, "}}")?;
                Ok(())
            }
            TraitRefKind::Dyn => write!(f, "{}", self.trait_decl_ref.with_ctx(ctx)),
            TraitRefKind::Unknown(msg) => write!(f, "UNKNOWN({msg})"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TraitTypeConstraint {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let trait_ref = self.trait_ref.with_ctx(ctx);
        let ty = self.ty.with_ctx(ctx);
        write!(f, "{trait_ref}::")?;
        ctx.format_assoc_type_name(f, self.trait_ref.trait_id(), self.type_id)?;
        write!(f, " = {ty}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for Ty {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self.kind() {
            // Print tuples as `(T1, T2, ...)` instead of `(_, _, ...)<T1, T2, ...>`.
            TyKind::Adt(tref)
                if tref.is_tuple()
                    && let Some(krate) = ctx.get_crate() =>
            {
                let fields = self.as_tuple_fields(krate);
                let trailing_comma = if fields.len() == 1 { "," } else { "" };
                let fields = fields.iter().map(|ty| ty.with_ctx(ctx)).format(", ");
                write!(f, "({fields}{trailing_comma})",)
            }
            TyKind::Adt(tref) if tref.is_str() => write!(f, "str"),
            TyKind::Adt(tref) => write!(f, "{}", tref.with_ctx(ctx)),
            TyKind::TypeVar(id) => write!(f, "{}", id.with_ctx(ctx)),
            TyKind::Scalar(kind) => write!(f, "{kind}"),
            TyKind::Never => write!(f, "!"),
            TyKind::Pattern(ty, pat) => write!(f, "{} is {}", ty.with_ctx(ctx), pat.with_ctx(ctx)),
            TyKind::Ref(r, ty, kind) => {
                write!(f, "&{} ", r.with_ctx(ctx))?;
                if let RefKind::Mut = kind {
                    write!(f, "mut ")?;
                }
                write!(f, "{}", ty.with_ctx(ctx))
            }
            TyKind::RawPtr(ty, kind) => {
                write!(f, "*")?;
                match kind {
                    RefKind::Shared => write!(f, "const")?,
                    RefKind::Mut => write!(f, "mut")?,
                }
                write!(f, " {}", ty.with_ctx(ctx))
            }
            TyKind::Array(ty, len, _) => {
                write!(f, "[{}; {}]", ty.with_ctx(ctx), len.with_ctx(ctx))
            }
            TyKind::Slice(ty, _) => {
                write!(f, "[{}]", ty.with_ctx(ctx))
            }
            TyKind::TraitType(trait_ref, type_id, generics) => {
                write!(f, "{}::", trait_ref.with_ctx(ctx))?;
                ctx.format_assoc_type_name(f, trait_ref.trait_id(), *type_id)?;
                write!(f, "{}", generics.with_ctx(ctx))
            }
            TyKind::DynTrait(pred) => {
                write!(f, "(dyn {})", pred.with_ctx(ctx))
            }
            TyKind::FnPtr(io) => {
                write!(f, "{}", io.with_ctx(ctx))
            }
            TyKind::FnDef(binder) => {
                let (regions, value) = binder.fmt_split(ctx);
                if !regions.is_empty() {
                    write!(f, "for<{regions}> ",)?
                };
                write!(f, "{value}",)
            }
            TyKind::PtrMetadata(ty) => {
                write!(f, "PtrMetadata<{}>", ty.with_ctx(ctx))
            }
            TyKind::Error(msg) => write!(f, "type_error(\"{msg}\")"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TypePattern {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            TypePattern::Range(start, end) => {
                write!(f, "{}..={}", start.with_ctx(ctx), end.with_ctx(ctx))
            }
            TypePattern::OrPattern(patterns) => {
                write!(
                    f,
                    "({})",
                    patterns.iter().map(|pat| pat.with_ctx(ctx)).format(" | ")
                )
            }
            TypePattern::NotNull => write!(f, "!null"),
        }
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TypeDbVar {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ctx.format_bound_var(f, *self, "@Type", |v| Some(v.name.clone()))
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TypeDecl {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let keyword = match &self.kind {
            TypeDeclKind::Struct(..) => "struct",
            TypeDeclKind::Union(..) => "union",
            TypeDeclKind::Enum(..) => "enum",
            TypeDeclKind::Alias(..) => "type",
            TypeDeclKind::Opaque | TypeDeclKind::Error(..) => "opaque type",
        };
        self.item_meta
            .fmt_item_intro(f, ctx, keyword, self.def_id)?;

        let ctx = &ctx.set_generics(&self.generics);
        let ctx = &ctx.set_current_type(self.def_id);
        let (params, preds) = self.generics.fmt_with_ctx_with_trait_clauses(ctx);
        write!(f, "{params}{preds}")?;

        let nl_or_space = if !self.generics.has_predicates() {
            " ".to_string()
        } else {
            "\n".to_string()
        };
        match &self.kind {
            TypeDeclKind::Struct(fields) => {
                write!(f, "{nl_or_space}{{")?;
                if !fields.is_empty() {
                    writeln!(f)?;
                    for field in fields {
                        writeln!(f, "  {},", field.with_ctx(ctx))?;
                    }
                }
                write!(f, "}}")
            }
            TypeDeclKind::Union(fields) => {
                write!(f, "{nl_or_space}{{")?;
                writeln!(f)?;
                for field in fields {
                    writeln!(f, "  {},", field.with_ctx(ctx))?;
                }
                write!(f, "}}")
            }
            TypeDeclKind::Enum(variants) => {
                write!(f, "{nl_or_space}{{")?;
                writeln!(f)?;
                for variant in variants {
                    writeln!(f, "  {},", variant.with_ctx(ctx))?;
                }
                write!(f, "}}")
            }
            TypeDeclKind::Alias(ty) => write!(f, " = {}", ty.with_ctx(ctx)),
            TypeDeclKind::Opaque => write!(f, ""),
            TypeDeclKind::Error(msg) => write!(f, " = ERROR({msg})"),
        }?;

        if ctx.include_layouts() {
            let layout_type_id = match &self.kind {
                TypeDeclKind::Alias(ty) => ty.as_adt().map(|tref| tref.id).unwrap_or(self.def_id),
                _ => self.def_id,
            };
            let ctx = &ctx.set_current_type(layout_type_id);
            let fmt_layout =
                |f: &mut fmt::Formatter<'_>, heading: &str, layout: &Layout| -> fmt::Result {
                    write!(f, "// {heading}:")?;
                    let ctx = &ctx.increase_indent();
                    for line in layout.to_string_with_ctx(ctx).lines() {
                        write!(f, "\n// {line}")?;
                    }
                    Ok(())
                };
            match self.layout.len() {
                0 => write!(f, "\n// layout: none")?,
                1 => {
                    let layout = self.layout.values().next().unwrap();
                    writeln!(f)?;
                    fmt_layout(f, "layout", layout)?;
                }
                _ => {
                    let mut separator = "\n";
                    for (target, layout) in &self.layout {
                        write!(f, "{separator}")?;
                        fmt_layout(f, &format!("layout for target `{target}`"), layout)?;
                        separator = "\n\n";
                    }
                }
            }
        }

        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TypeDeclId {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        ItemId::from(*self).fmt_with_ctx(ctx, f)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TypeDeclRef {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let id = self.id.with_ctx(ctx);
        let generics = self.generics.with_ctx(ctx);
        write!(f, "{id}{generics}")
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for TypeParam {
    fn fmt_with_ctx(&self, _ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.name)
    }
}

impl<C: AstFormatter> FmtWithCtx<C> for UnOp {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            UnOp::Not => write!(f, "~"),
            UnOp::Neg(mode) => write!(f, "{}.-", mode),
            UnOp::Cast(kind) => write!(f, "{}", kind.with_ctx(ctx)),
        }
    }
}

impl_display_via_ctx!(Variant);
impl<C: AstFormatter> FmtWithCtx<C> for Variant {
    fn fmt_with_ctx(&self, ctx: &C, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.name)?;
        if !self.fields.is_empty() {
            let fields = self.fields.iter().map(|f| f.with_ctx(ctx)).format(", ");
            write!(f, " {{ {} }}", fields)?;
        }
        Ok(())
    }
}

impl<C: AstFormatter> FmtWithCtx<(&C, VariantId)> for VariantLayout {
    fn fmt_with_ctx(
        &self,
        &(ctx, variant_id): &(&C, VariantId),
        f: &mut fmt::Formatter<'_>,
    ) -> fmt::Result {
        writeln!(f, "{{")?;
        let tab = ctx.indent();
        let ctx1 = &ctx.increase_indent();
        let tab1 = ctx1.indent();
        for (field_id, offset) in self.field_offsets.iter_enumerated() {
            write!(f, "{tab1}offset of ")?;
            ctx1.format_current_field_name(f, variant_id, field_id)?;
            writeln!(f, ": {},", offset.with_ctx(ctx1))?;
        }
        let tagger = self
            .tagger
            .iter()
            .map(|(offset, value)| format!("{offset} := {value}"))
            .format(", ");
        writeln!(f, "{tab1}inhabited: {},", self.inhabited.with_ctx(ctx1))?;
        writeln!(f, "{tab1}tagger: [{tagger}],")?;
        write!(f, "{tab}}}")
    }
}