rust-analyzer

diff --git a/crates/hir-ty/src/display.rs b/crates/hir-ty/src/display.rs
index 43b428c3fa..4e77e8be36 100644
--- a/crates/hir-ty/src/display.rs
+++ b/crates/hir-ty/src/display.rs

@@ -12,7 +12,6 @@ use either::Either;

use hir_def::{

FindPathConfig, GenericDefId, GenericParamId, HasModule, LocalFieldId, Lookup, ModuleDefId,

ModuleId, TraitId,

- db::DefDatabase,

expr_store::{ExpressionStore, path::Path},

find_path::{self, PrefixKind},

hir::generics::{TypeOrConstParamData, TypeParamProvenance, WherePredicate},

@@ -100,6 +99,9 @@ pub struct HirFormatter<'a, 'db> {

display_kind: DisplayKind,

display_target: DisplayTarget,

bounds_formatting_ctx: BoundsFormattingCtx<'db>,

+ /// Whether formatting `impl Trait1 + Trait2` or `dyn Trait1 + Trait2` needs parentheses around it,

+ /// for example when formatting `&(impl Trait1 + Trait2)`.

+ trait_bounds_need_parens: bool,

}

// FIXME: To consider, ref and dyn trait lifetimes can be omitted if they are `'_`, path args should

@@ -331,6 +333,7 @@ pub trait HirDisplay<'db> {

show_container_bounds: false,

display_lifetimes: DisplayLifetime::OnlyNamedOrStatic,

bounds_formatting_ctx: Default::default(),

+ trait_bounds_need_parens: false,

}) {

Ok(()) => {}

Err(HirDisplayError::FmtError) => panic!("Writing to String can't fail!"),

@@ -566,6 +569,7 @@ impl<'db, T: HirDisplay<'db>> HirDisplayWrapper<'_, 'db, T> {

show_container_bounds: self.show_container_bounds,

display_lifetimes: self.display_lifetimes,

bounds_formatting_ctx: Default::default(),

+ trait_bounds_need_parens: false,

})

}

@@ -612,7 +616,11 @@ impl<'db, T: HirDisplay<'db> + Internable> HirDisplay<'db> for Interned<T> {

}

-fn write_projection<'db>(f: &mut HirFormatter<'_, 'db>, alias: &AliasTy<'db>) -> Result {

+fn write_projection<'db>(

+ f: &mut HirFormatter<'_, 'db>,

+ alias: &AliasTy<'db>,

+ needs_parens_if_multi: bool,

+) -> Result {

if f.should_truncate() {

return write!(f, "{TYPE_HINT_TRUNCATION}");

}

@@ -650,6 +658,7 @@ fn write_projection<'db>(f: &mut HirFormatter<'_, 'db>, alias: &AliasTy<'db>) ->

Either::Left(Ty::new_alias(f.interner, AliasTyKind::Projection, *alias)),

&bounds,

SizedByDefault::NotSized,

+ needs_parens_if_multi,

)

});

}

@@ -1056,7 +1065,7 @@ impl<'db> HirDisplay<'db> for Ty<'db> {

return write!(f, "{TYPE_HINT_TRUNCATION}");

}

- use TyKind;

+ let trait_bounds_need_parens = mem::replace(&mut f.trait_bounds_need_parens, false);

match self.kind() {

TyKind::Never => write!(f, "!")?,

TyKind::Str => write!(f, "str")?,

@@ -1077,103 +1086,34 @@ impl<'db> HirDisplay<'db> for Ty<'db> {

c.hir_fmt(f)?;

write!(f, "]")?;

}

- kind @ (TyKind::RawPtr(t, m) | TyKind::Ref(_, t, m)) => {

- if let TyKind::Ref(l, _, _) = kind {

- f.write_char('&')?;

- if f.render_region(l) {

- l.hir_fmt(f)?;

- f.write_char(' ')?;

- }

- match m {

- rustc_ast_ir::Mutability::Not => (),

- rustc_ast_ir::Mutability::Mut => f.write_str("mut ")?,

- }

- } else {

- write!(

- f,

- "*{}",

- match m {

- rustc_ast_ir::Mutability::Not => "const ",

- rustc_ast_ir::Mutability::Mut => "mut ",

- }

- )?;

+ TyKind::Ref(l, t, m) => {

+ f.write_char('&')?;

+ if f.render_region(l) {

+ l.hir_fmt(f)?;

+ f.write_char(' ')?;

+ }

+ match m {

+ rustc_ast_ir::Mutability::Not => (),

+ rustc_ast_ir::Mutability::Mut => f.write_str("mut ")?,

}

- // FIXME: all this just to decide whether to use parentheses...

- let (preds_to_print, has_impl_fn_pred) = match t.kind() {

- TyKind::Dynamic(bounds, region) => {

- let contains_impl_fn =

- bounds.iter().any(|bound| match bound.skip_binder() {

- ExistentialPredicate::Trait(trait_ref) => {

- let trait_ = trait_ref.def_id.0;

- fn_traits(f.lang_items()).any(|it| it == trait_)

- }

- _ => false,

- });

- let render_lifetime = f.render_region(region);

- (bounds.len() + render_lifetime as usize, contains_impl_fn)

- }

- TyKind::Alias(AliasTyKind::Opaque, ty) => {

- let opaque_ty_id = match ty.def_id {

- SolverDefId::InternedOpaqueTyId(id) => id,

- _ => unreachable!(),

- };

- let impl_trait_id = db.lookup_intern_impl_trait_id(opaque_ty_id);

- if let ImplTraitId::ReturnTypeImplTrait(func, _) = impl_trait_id {

- let data = impl_trait_id.predicates(db);

- let bounds =

- || data.iter_instantiated_copied(f.interner, ty.args.as_slice());

- let mut len = bounds().count();

- // Don't count Sized but count when it absent

- // (i.e. when explicit ?Sized bound is set).

- let default_sized = SizedByDefault::Sized { anchor: func.krate(db) };

- let sized_bounds = bounds()

- .filter(|b| {

- matches!(

- b.kind().skip_binder(),

- ClauseKind::Trait(trait_ref)

- if default_sized.is_sized_trait(

- trait_ref.def_id().0,

- db,

- ),

- )

- })

- .count();

- match sized_bounds {

- 0 => len += 1,

- _ => {

- len = len.saturating_sub(sized_bounds);

- }

- let contains_impl_fn = bounds().any(|bound| {

- if let ClauseKind::Trait(trait_ref) = bound.kind().skip_binder() {

- let trait_ = trait_ref.def_id().0;

- fn_traits(f.lang_items()).any(|it| it == trait_)

- } else {

- false

- }

- });

- (len, contains_impl_fn)

- } else {

- (0, false)

- }

+ f.trait_bounds_need_parens = true;

+ t.hir_fmt(f)?;

+ f.trait_bounds_need_parens = false;

+ }

+ TyKind::RawPtr(t, m) => {

+ write!(

+ f,

+ "*{}",

+ match m {

+ rustc_ast_ir::Mutability::Not => "const ",

+ rustc_ast_ir::Mutability::Mut => "mut ",

}

- _ => (0, false),

- };

- if has_impl_fn_pred && preds_to_print <= 2 {

- return t.hir_fmt(f);

- }

+ )?;

- if preds_to_print > 1 {

- write!(f, "(")?;

- t.hir_fmt(f)?;

- write!(f, ")")?;

- } else {

- t.hir_fmt(f)?;

- }

+ f.trait_bounds_need_parens = true;

+ t.hir_fmt(f)?;

+ f.trait_bounds_need_parens = false;

}

TyKind::Tuple(tys) => {

if tys.len() == 1 {

@@ -1328,7 +1268,9 @@ impl<'db> HirDisplay<'db> for Ty<'db> {

hir_fmt_generics(f, parameters.as_slice(), Some(def.def_id().0.into()), None)?;

}

- TyKind::Alias(AliasTyKind::Projection, alias_ty) => write_projection(f, &alias_ty)?,

+ TyKind::Alias(AliasTyKind::Projection, alias_ty) => {

+ write_projection(f, &alias_ty, trait_bounds_need_parens)?

+ }

TyKind::Foreign(alias) => {

let type_alias = db.type_alias_signature(alias.0);

f.start_location_link(alias.0.into());

@@ -1363,6 +1305,7 @@ impl<'db> HirDisplay<'db> for Ty<'db> {

Either::Left(*self),

&bounds,

SizedByDefault::Sized { anchor: krate },

+ trait_bounds_need_parens,

)?;

}

TyKind::Closure(id, substs) => {

@@ -1525,6 +1468,7 @@ impl<'db> HirDisplay<'db> for Ty<'db> {

Either::Left(*self),

&bounds,

SizedByDefault::Sized { anchor: krate },

+ trait_bounds_need_parens,

)?;

}

@@ -1567,6 +1511,7 @@ impl<'db> HirDisplay<'db> for Ty<'db> {

Either::Left(*self),

&bounds_to_display,

SizedByDefault::NotSized,

+ trait_bounds_need_parens,

)?;

}

TyKind::Error(_) => {

@@ -1806,11 +1751,11 @@ pub enum SizedByDefault {

}

impl SizedByDefault {

- fn is_sized_trait(self, trait_: TraitId, db: &dyn DefDatabase) -> bool {

+ fn is_sized_trait(self, trait_: TraitId, interner: DbInterner<'_>) -> bool {

match self {

Self::NotSized => false,

- Self::Sized { anchor } => {

- let sized_trait = hir_def::lang_item::lang_items(db, anchor).Sized;

+ Self::Sized { .. } => {

+ let sized_trait = interner.lang_items().Sized;

Some(trait_) == sized_trait

}

@@ -1823,16 +1768,62 @@ pub fn write_bounds_like_dyn_trait_with_prefix<'db>(

this: Either<Ty<'db>, Region<'db>>,

predicates: &[Clause<'db>],

default_sized: SizedByDefault,

+ needs_parens_if_multi: bool,

) -> Result {

+ let needs_parens =

+ needs_parens_if_multi && trait_bounds_need_parens(f, this, predicates, default_sized);

+ if needs_parens {

+ write!(f, "(")?;

+ }

write!(f, "{prefix}")?;

if !predicates.is_empty()

|| predicates.is_empty() && matches!(default_sized, SizedByDefault::Sized { .. })

{

write!(f, " ")?;

- write_bounds_like_dyn_trait(f, this, predicates, default_sized)

- } else {

- Ok(())

+ write_bounds_like_dyn_trait(f, this, predicates, default_sized)?;

+ }

+ if needs_parens {

+ write!(f, ")")?;

+ }

+ Ok(())

+fn trait_bounds_need_parens<'db>(

+ f: &mut HirFormatter<'_, 'db>,

+ this: Either<Ty<'db>, Region<'db>>,

+ predicates: &[Clause<'db>],

+ default_sized: SizedByDefault,

+) -> bool {

+ // This needs to be kept in sync with `write_bounds_like_dyn_trait()`.

+ let mut distinct_bounds = 0usize;

+ let mut is_sized = false;

+ for p in predicates {

+ match p.kind().skip_binder() {

+ ClauseKind::Trait(trait_ref) => {

+ let trait_ = trait_ref.def_id().0;

+ if default_sized.is_sized_trait(trait_, f.interner) {

+ is_sized = true;

+ if matches!(default_sized, SizedByDefault::Sized { .. }) {

+ // Don't print +Sized, but rather +?Sized if absent.

+ continue;

+ }

+ distinct_bounds += 1;

+ }

+ ClauseKind::TypeOutlives(to) if Either::Left(to.0) == this => distinct_bounds += 1,

+ ClauseKind::RegionOutlives(lo) if Either::Right(lo.0) == this => distinct_bounds += 1,

+ _ => {}

+ }

}

+ if let SizedByDefault::Sized { .. } = default_sized

+ && !is_sized

+ {

+ distinct_bounds += 1;

+ }

+ distinct_bounds > 1

}

fn write_bounds_like_dyn_trait<'db>(

@@ -1855,7 +1846,7 @@ fn write_bounds_like_dyn_trait<'db>(

match p.kind().skip_binder() {

ClauseKind::Trait(trait_ref) => {

let trait_ = trait_ref.def_id().0;

- if default_sized.is_sized_trait(trait_, f.db) {

+ if default_sized.is_sized_trait(trait_, f.interner) {

is_sized = true;

if matches!(default_sized, SizedByDefault::Sized { .. }) {

// Don't print +Sized, but rather +?Sized if absent.

diff --git a/crates/hir-ty/src/tests/coercion.rs b/crates/hir-ty/src/tests/coercion.rs
index 36630ab587..438699b409 100644
--- a/crates/hir-ty/src/tests/coercion.rs
+++ b/crates/hir-ty/src/tests/coercion.rs

@@ -608,7 +608,7 @@ trait Foo {}

fn test(f: impl Foo, g: &(impl Foo + ?Sized)) {

let _: &dyn Foo = &f;

let _: &dyn Foo = g;

- //^ expected &'? (dyn Foo + 'static), got &'? impl Foo + ?Sized

+ //^ expected &'? (dyn Foo + 'static), got &'? (impl Foo + ?Sized)

}

"#,

);

diff --git a/crates/hir-ty/src/tests/display_source_code.rs b/crates/hir-ty/src/tests/display_source_code.rs
index dc3869930d..37da7fc875 100644
--- a/crates/hir-ty/src/tests/display_source_code.rs
+++ b/crates/hir-ty/src/tests/display_source_code.rs

@@ -111,7 +111,7 @@ fn test(

//^ impl Foo

- //^ &impl Foo + ?Sized

+ //^ &(impl Foo + ?Sized)

//^ S<impl Foo>

ref_any;

@@ -192,7 +192,7 @@ fn test(

//^ fn(impl Foo) -> impl Foo

-} //^ fn(&impl Foo + ?Sized) -> &impl Foo + ?Sized

+} //^ fn(&(impl Foo + ?Sized)) -> &(impl Foo + ?Sized)

"#,

);

}

diff --git a/crates/hir-ty/src/tests/traits.rs b/crates/hir-ty/src/tests/traits.rs
index 390553c0d7..1a0bd44798 100644
--- a/crates/hir-ty/src/tests/traits.rs
+++ b/crates/hir-ty/src/tests/traits.rs

@@ -4819,7 +4819,7 @@ fn allowed3(baz: impl Baz<Assoc = Qux<impl Foo>>) {}

431..433 '{}': ()

447..450 'baz': impl Baz<Assoc = impl Foo>

480..482 '{}': ()

- 500..503 'baz': impl Baz<Assoc = &'a impl Foo + 'a>

+ 500..503 'baz': impl Baz<Assoc = &'a (impl Foo + 'a)>

544..546 '{}': ()

560..563 'baz': impl Baz<Assoc = Qux<impl Foo>>

598..600 '{}': ()

diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 1f9af564c3..b4440dfa18 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs

@@ -587,6 +587,7 @@ impl<'db> HirDisplay<'db> for TypeParam {

Either::Left(ty),

&predicates,

SizedByDefault::Sized { anchor: krate },

+ false,

);

}

@@ -614,6 +615,7 @@ impl<'db> HirDisplay<'db> for TypeParam {

Either::Left(ty),

&predicates,

default_sized,

+ false,

)?;

}

Ok(())

diff --git a/crates/ide/src/inlay_hints/bind_pat.rs b/crates/ide/src/inlay_hints/bind_pat.rs
index c74e3104c1..caf7cc714d 100644
--- a/crates/ide/src/inlay_hints/bind_pat.rs
+++ b/crates/ide/src/inlay_hints/bind_pat.rs

@@ -1382,4 +1382,21 @@ fn f<'a>() {

"#]],

);

}

+ #[test]

+ fn ref_multi_trait_impl_trait() {

+ check_with_config(

+ InlayHintsConfig { type_hints: true, ..DISABLED_CONFIG },

+ r#"

+//- minicore: sized

+trait Eq {}

+trait Ord {}

+fn foo(argument: &(impl Eq + Ord)) {

+ let x = argument;

+ // ^ &(impl Eq + Ord)

+ "#,

+ );

+ }

}