Parse lifetime bounds in lifetime param into TypeBoundList

This mainly aids in error recovery but also makes it a bit easier to handle lifetime resolution.
While doing so it also came apparent that we were not actually lowering lifetime outlives relationships within lifetime parameter declaration bounds, so this fixes that.

14 files changed, 125 insertions, 85 deletions

diff --git a/src/tools/rust-analyzer/crates/hir-def/src/item_tree/pretty.rs b/src/tools/rust-analyzer/crates/hir-def/src/item_tree/pretty.rs
index 0c5e3a3620a..70bf2f13c88 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/item_tree/pretty.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/item_tree/pretty.rs
@@ -648,9 +648,9 @@ impl Printer<'_> {
                 let (target, bound) = match pred {
                     WherePredicate::TypeBound { target, bound } => (target, bound),
                     WherePredicate::Lifetime { target, bound } => {
-                        wln!(
+                        w!(
                             this,
-                            "{}: {},",
+                            "{}: {}",
                             target.name.display(self.db.upcast(), edition),
                             bound.name.display(self.db.upcast(), edition)
                         );
diff --git a/src/tools/rust-analyzer/crates/hir-def/src/item_tree/tests.rs b/src/tools/rust-analyzer/crates/hir-def/src/item_tree/tests.rs
index 5c07369f4b5..0f53969d6c7 100644
--- a/src/tools/rust-analyzer/crates/hir-def/src/item_tree/tests.rs
+++ b/src/tools/rust-analyzer/crates/hir-def/src/item_tree/tests.rs
@@ -351,7 +351,8 @@ trait Tr<'a, T: 'a>: Super where Self: for<'a> Tr<'a, T> {}
             where
                 T: Copy,
                 T: 'a,
-                T: 'b
+                T: 'b,
+                'b: 'a
             {
                 pub(self) field: &'a &'b T,
             }
@@ -370,7 +371,8 @@ trait Tr<'a, T: 'a>: Super where Self: for<'a> Tr<'a, T> {}
             where
                 T: Copy,
                 T: 'a,
-                T: 'b
+                T: 'b,
+                'b: 'a
             {
                 // AstId: 9
                 pub(self) fn f<G>(
diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs b/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs
index 624148cab20..b62672d21e8 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs
@@ -1631,6 +1631,29 @@ fn test<'lifetime>(
 }
 
 #[test]
+fn lifetime_bounds() {
+    check_infer(
+        r#"
+//- minicore: sized, coerce_unsized
+trait Trait<'a>: Sized {
+    fn f(&'a self) {}
+}
+fn test<'a, 'b: 'a>(it: impl Trait<'a>){
+    it.f();
+}
+"#,
+        expect![[r#"
+            38..42 'self': &'a Self
+            44..46 '{}': ()
+            69..71 'it': impl Trait<'a>
+            88..103 '{     it.f(); }': ()
+            94..96 'it': impl Trait<'a>
+            94..100 'it.f()': ()
+        "#]],
+    );
+}
+
+#[test]
 fn error_bound_chalk() {
     check_types(
         r#"
diff --git a/src/tools/rust-analyzer/crates/hir/src/semantics.rs b/src/tools/rust-analyzer/crates/hir/src/semantics.rs
index 65470d061b3..0b09cf27926 100644
--- a/src/tools/rust-analyzer/crates/hir/src/semantics.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/semantics.rs
@@ -2026,6 +2026,10 @@ impl SemanticsScope<'_> {
         )
     }
 
+    pub fn generic_def(&self) -> Option<crate::GenericDef> {
+        self.resolver.generic_def().map(|id| id.into())
+    }
+
     pub fn extern_crates(&self) -> impl Iterator<Item = (Name, Module)> + '_ {
         self.resolver.extern_crates_in_scope().map(|(name, id)| (name, Module { id }))
     }
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/completions/lifetime.rs b/src/tools/rust-analyzer/crates/ide-completion/src/completions/lifetime.rs
index 9efc52428ef..0692446381b 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/completions/lifetime.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/completions/lifetime.rs
@@ -8,7 +8,6 @@
 //! show up for normal completions, or they won't show completions other than lifetimes depending
 //! on the fixture input.
 use hir::{sym, Name, ScopeDef};
-use syntax::{ast, ToSmolStr, TokenText};
 
 use crate::{
     completions::Completions,
@@ -21,33 +20,24 @@ pub(crate) fn complete_lifetime(
     ctx: &CompletionContext<'_>,
     lifetime_ctx: &LifetimeContext,
 ) {
-    let (lp, lifetime) = match lifetime_ctx {
-        LifetimeContext { kind: LifetimeKind::Lifetime, lifetime } => (None, lifetime),
-        LifetimeContext {
-            kind: LifetimeKind::LifetimeParam { is_decl: false, param },
-            lifetime,
-        } => (Some(param), lifetime),
-        _ => return,
-    };
-    let param_lifetime = match (lifetime, lp.and_then(|lp| lp.lifetime())) {
-        (Some(lt), Some(lp)) if lp == lt.clone() => return,
-        (Some(_), Some(lp)) => Some(lp),
-        _ => None,
+    let &LifetimeContext { kind: LifetimeKind::Lifetime { in_lifetime_param_bound, def }, .. } =
+        lifetime_ctx
+    else {
+        return;
     };
-    let param_lifetime = param_lifetime.as_ref().map(ast::Lifetime::text);
-    let param_lifetime = param_lifetime.as_ref().map(TokenText::as_str);
 
     ctx.process_all_names_raw(&mut |name, res| {
-        if matches!(
-            res,
-            ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_))
-                 if param_lifetime != Some(&*name.display_no_db(ctx.edition).to_smolstr())
-        ) {
+        if matches!(res, ScopeDef::GenericParam(hir::GenericParam::LifetimeParam(_))) {
             acc.add_lifetime(ctx, name);
         }
     });
-    if param_lifetime.is_none() {
-        acc.add_lifetime(ctx, Name::new_symbol_root(sym::tick_static.clone()));
+    acc.add_lifetime(ctx, Name::new_symbol_root(sym::tick_static.clone()));
+    if !in_lifetime_param_bound
+        && def.is_some_and(|def| {
+            !matches!(def, hir::GenericDef::Function(_) | hir::GenericDef::Impl(_))
+        })
+    {
+        acc.add_lifetime(ctx, Name::new_symbol_root(sym::tick_underscore.clone()));
     }
 }
 
@@ -222,6 +212,8 @@ fn foo<'footime, 'lifetime: 'a$0>() {}
 "#,
             expect![[r#"
                 lt 'footime
+                lt 'lifetime
+                lt 'static
             "#]],
         );
     }
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/context.rs b/src/tools/rust-analyzer/crates/ide-completion/src/context.rs
index 5b8d1c30a29..3a661706336 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/context.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/context.rs
@@ -290,15 +290,14 @@ pub(crate) struct ParamContext {
 /// The state of the lifetime we are completing.
 #[derive(Debug)]
 pub(crate) struct LifetimeContext {
-    pub(crate) lifetime: Option<ast::Lifetime>,
     pub(crate) kind: LifetimeKind,
 }
 
 /// The kind of lifetime we are completing.
 #[derive(Debug)]
 pub(crate) enum LifetimeKind {
-    LifetimeParam { is_decl: bool, param: ast::LifetimeParam },
-    Lifetime,
+    LifetimeParam,
+    Lifetime { in_lifetime_param_bound: bool, def: Option<hir::GenericDef> },
     LabelRef,
     LabelDef,
 }
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs b/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs
index a4e018b1800..4a678963b93 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/context/analysis.rs
@@ -562,7 +562,7 @@ fn expected_type_and_name(
 }
 
 fn classify_lifetime(
-    _sema: &Semantics<'_, RootDatabase>,
+    sema: &Semantics<'_, RootDatabase>,
     original_file: &SyntaxNode,
     lifetime: ast::Lifetime,
 ) -> Option<LifetimeContext> {
@@ -571,21 +571,22 @@ fn classify_lifetime(
         return None;
     }
 
+    let lifetime =
+        find_node_at_offset::<ast::Lifetime>(original_file, lifetime.syntax().text_range().start());
     let kind = match_ast! {
         match parent {
-            ast::LifetimeParam(param) => LifetimeKind::LifetimeParam {
-                is_decl: param.lifetime().as_ref() == Some(&lifetime),
-                param
-            },
+            ast::LifetimeParam(_) => LifetimeKind::LifetimeParam,
             ast::BreakExpr(_) => LifetimeKind::LabelRef,
             ast::ContinueExpr(_) => LifetimeKind::LabelRef,
             ast::Label(_) => LifetimeKind::LabelDef,
-            _ => LifetimeKind::Lifetime,
+            _ => {
+                let def = lifetime.as_ref().and_then(|lt| sema.scope(lt.syntax())?.generic_def());
+                LifetimeKind::Lifetime { in_lifetime_param_bound: ast::TypeBound::can_cast(parent.kind()), def }
+            },
         }
     };
-    let lifetime = find_node_at_offset(original_file, lifetime.syntax().text_range().start());
 
-    Some(LifetimeContext { lifetime, kind })
+    Some(LifetimeContext { kind })
 }
 
 fn classify_name(
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/defs.rs b/src/tools/rust-analyzer/crates/ide-db/src/defs.rs
index fdac4dd2efb..5eec33636be 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/defs.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/defs.rs
@@ -772,16 +772,6 @@ impl NameRefClass {
                 .map(GenericParam::LifetimeParam)
                 .map(Definition::GenericParam)
                 .map(NameRefClass::Definition),
-            // lifetime bounds, as in the 'b in 'a: 'b aren't wrapped in TypeBound nodes so we gotta check
-            // if our lifetime is in a LifetimeParam without being the constrained lifetime
-            _ if ast::LifetimeParam::cast(parent).and_then(|param| param.lifetime()).as_ref()
-                != Some(lifetime) =>
-            {
-                sema.resolve_lifetime_param(lifetime)
-                    .map(GenericParam::LifetimeParam)
-                    .map(Definition::GenericParam)
-                    .map(NameRefClass::Definition)
-            }
             _ => None,
         }
     }
diff --git a/src/tools/rust-analyzer/crates/intern/src/symbol/symbols.rs b/src/tools/rust-analyzer/crates/intern/src/symbol/symbols.rs
index 8f79cf20079..ebc9c14059d 100644
--- a/src/tools/rust-analyzer/crates/intern/src/symbol/symbols.rs
+++ b/src/tools/rust-analyzer/crates/intern/src/symbol/symbols.rs
@@ -80,6 +80,7 @@ define_symbols! {
     self_ = "self",
     Self_ = "Self",
     tick_static = "'static",
+    tick_underscore = "'_",
     dollar_crate = "$crate",
     MISSING_NAME = "[missing name]",
     fn_ = "fn",
diff --git a/src/tools/rust-analyzer/crates/parser/src/grammar/generic_params.rs b/src/tools/rust-analyzer/crates/parser/src/grammar/generic_params.rs
index 08b23cd92a6..9d4fdbfaf2e 100644
--- a/src/tools/rust-analyzer/crates/parser/src/grammar/generic_params.rs
+++ b/src/tools/rust-analyzer/crates/parser/src/grammar/generic_params.rs
@@ -56,7 +56,7 @@ fn generic_param(p: &mut Parser<'_>, m: Marker) -> bool {
 fn lifetime_param(p: &mut Parser<'_>, m: Marker) {
     assert!(p.at(LIFETIME_IDENT));
     lifetime(p);
-    if p.at(T![:]) {
+    if p.eat(T![:]) {
         lifetime_bounds(p);
     }
     m.complete(p, LIFETIME_PARAM);
@@ -106,14 +106,19 @@ fn const_param(p: &mut Parser<'_>, m: Marker) {
 }
 
 fn lifetime_bounds(p: &mut Parser<'_>) {
-    assert!(p.at(T![:]));
-    p.bump(T![:]);
-    while p.at(LIFETIME_IDENT) {
-        lifetime(p);
+    let marker = p.start();
+    while {
+        if !matches!(p.current(), LIFETIME_IDENT | T![>] | T![,]) {
+            p.error("expected lifetime");
+        }
+
+        type_bound(p)
+    } {
         if !p.eat(T![+]) {
             break;
         }
     }
+    marker.complete(p, TYPE_BOUND_LIST);
 }
 
 // test type_param_bounds
diff --git a/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/lifetime_param.rast b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/lifetime_param.rast
index c595031f358..315200aca21 100644
--- a/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/lifetime_param.rast
+++ b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/lifetime_param.rast
@@ -11,8 +11,10 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
       R_ANGLE ">"
     PARAM_LIST
       L_PAREN "("
diff --git a/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/precise_capturing.rast b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/precise_capturing.rast
index f9c0a245af8..5a67cc21766 100644
--- a/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/precise_capturing.rast
+++ b/src/tools/rust-analyzer/crates/parser/test_data/parser/inline/ok/precise_capturing.rast
@@ -11,8 +11,10 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'a"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'a"
       COMMA ","
       WHITESPACE " "
       LIFETIME_PARAM
@@ -20,8 +22,10 @@ SOURCE_FILE
           LIFETIME_IDENT "'b"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
       COMMA ","
       WHITESPACE " "
       TYPE_PARAM
diff --git a/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0018_struct_type_params.rast b/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0018_struct_type_params.rast
index 11ebc7efb9f..1e4eb156095 100644
--- a/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0018_struct_type_params.rast
+++ b/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0018_struct_type_params.rast
@@ -96,6 +96,7 @@ SOURCE_FILE
         LIFETIME
           LIFETIME_IDENT "'a"
         COLON ":"
+        TYPE_BOUND_LIST
       R_ANGLE ">"
     SEMICOLON ";"
   WHITESPACE "\n"
@@ -111,8 +112,10 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
       R_ANGLE ">"
     SEMICOLON ";"
   WHITESPACE "\n"
@@ -128,10 +131,12 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
-        WHITESPACE " "
-        PLUS "+"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
+          WHITESPACE " "
+          PLUS "+"
       WHITESPACE " "
       R_ANGLE ">"
     SEMICOLON ";"
@@ -148,13 +153,16 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
-        WHITESPACE " "
-        PLUS "+"
-        WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'c"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
+          WHITESPACE " "
+          PLUS "+"
+          WHITESPACE " "
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'c"
       R_ANGLE ">"
     SEMICOLON ";"
   WHITESPACE "\n"
@@ -202,9 +210,11 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
-        PLUS "+"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
+          PLUS "+"
       COMMA ","
       WHITESPACE " "
       LIFETIME_PARAM
@@ -212,8 +222,10 @@ SOURCE_FILE
           LIFETIME_IDENT "'b"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'c"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'c"
       COMMA ","
       R_ANGLE ">"
     SEMICOLON ";"
diff --git a/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0020_type_param_bounds.rast b/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0020_type_param_bounds.rast
index 043a966ff97..448cf49446e 100644
--- a/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0020_type_param_bounds.rast
+++ b/src/tools/rust-analyzer/crates/parser/test_data/parser/ok/0020_type_param_bounds.rast
@@ -237,8 +237,10 @@ SOURCE_FILE
           LIFETIME_IDENT "'a"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'d"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'d"
       COMMA ","
       WHITESPACE " "
       LIFETIME_PARAM
@@ -246,13 +248,16 @@ SOURCE_FILE
           LIFETIME_IDENT "'d"
         COLON ":"
         WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'a"
-        WHITESPACE " "
-        PLUS "+"
-        WHITESPACE " "
-        LIFETIME
-          LIFETIME_IDENT "'b"
+        TYPE_BOUND_LIST
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'a"
+          WHITESPACE " "
+          PLUS "+"
+          WHITESPACE " "
+          TYPE_BOUND
+            LIFETIME
+              LIFETIME_IDENT "'b"
       COMMA ","
       WHITESPACE " "
       TYPE_PARAM