Rollup merge of #96989 - cjgillot:defpath-use, r=davidtwco

Be more precise than DefPathData::Misc.

This variant was used for two unrelated things. Let's make this cleaner.

compiler/rustc_hir/src/definitions.rs

@@ -261,14 +261,16 @@ pub enum DefPathData {
     // they are treated specially by the `def_path` function.
     /// The crate root (marker).
     CrateRoot,
-    // Catch-all for random `DefId` things like `DUMMY_NODE_ID`.
-    Misc,
 
     // Different kinds of items and item-like things:
     /// An impl.
     Impl,
     /// An `extern` block.
     ForeignMod,
+    /// A `use` item.
+    Use,
+    /// A global asm item.
+    GlobalAsm,
     /// Something in the type namespace.
     TypeNs(Symbol),
     /// Something in the value namespace.
@@ -443,9 +445,8 @@ impl DefPathData {
         match *self {
             TypeNs(name) | ValueNs(name) | MacroNs(name) | LifetimeNs(name) => Some(name),
 
-            Impl | ForeignMod | CrateRoot | Misc | ClosureExpr | Ctor | AnonConst | ImplTrait => {
+            Impl | ForeignMod | CrateRoot | Use | GlobalAsm | ClosureExpr | Ctor | AnonConst
-                None
+            | ImplTrait => None,
-            }
         }
     }
 
@@ -459,7 +460,8 @@ impl DefPathData {
             CrateRoot => DefPathDataName::Anon { namespace: kw::Crate },
             Impl => DefPathDataName::Anon { namespace: kw::Impl },
             ForeignMod => DefPathDataName::Anon { namespace: kw::Extern },
-            Misc => DefPathDataName::Anon { namespace: sym::misc },
+            Use => DefPathDataName::Anon { namespace: kw::Use },
+            GlobalAsm => DefPathDataName::Anon { namespace: sym::global_asm },
             ClosureExpr => DefPathDataName::Anon { namespace: sym::closure },
             Ctor => DefPathDataName::Anon { namespace: sym::constructor },
             AnonConst => DefPathDataName::Anon { namespace: sym::constant },

compiler/rustc_middle/src/ty/mod.rs

@@ -1994,6 +1994,7 @@ impl<'tcx> TyCtxt<'tcx> {
             .filter(|item| item.kind == AssocKind::Fn && item.defaultness.has_value())
     }
 
+    /// Look up the name of a definition across crates. This does not look at HIR.
     fn opt_item_name(self, def_id: DefId) -> Option<Symbol> {
         if let Some(cnum) = def_id.as_crate_root() {
             Some(self.crate_name(cnum))
@@ -2014,16 +2015,11 @@ impl<'tcx> TyCtxt<'tcx> {
 
     /// Look up the name of a definition across crates. This does not look at HIR.
     ///
-    /// When possible, this function should be used for cross-crate lookups over
+    /// This method will ICE if the corresponding item does not have a name.  In these cases, use
-    /// [`opt_item_name`] to avoid invalidating the incremental cache. If you
-    /// need to handle items without a name, or HIR items that will not be
-    /// serialized cross-crate, or if you need the span of the item, use
     /// [`opt_item_name`] instead.
     ///
     /// [`opt_item_name`]: Self::opt_item_name
     pub fn item_name(self, id: DefId) -> Symbol {
-        // Look at cross-crate items first to avoid invalidating the incremental cache
-        // unless we have to.
         self.opt_item_name(id).unwrap_or_else(|| {
             bug!("item_name: no name for {:?}", self.def_path(id));
         })

compiler/rustc_resolve/src/def_collector.rs

@@ -109,7 +109,7 @@ impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
                 visit::walk_item(self, i);
                 return self.visit_macro_invoc(i.id);
             }
-            ItemKind::GlobalAsm(..) => DefPathData::Misc,
+            ItemKind::GlobalAsm(..) => DefPathData::GlobalAsm,
             ItemKind::Use(..) => {
                 return visit::walk_item(self, i);
             }
@@ -160,11 +160,11 @@ impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
     }
 
     fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
-        self.create_def(id, DefPathData::Misc, use_tree.span);
+        self.create_def(id, DefPathData::Use, use_tree.span);
         match use_tree.kind {
             UseTreeKind::Simple(_, id1, id2) => {
-                self.create_def(id1, DefPathData::Misc, use_tree.prefix.span);
+                self.create_def(id1, DefPathData::Use, use_tree.prefix.span);
-                self.create_def(id2, DefPathData::Misc, use_tree.prefix.span);
+                self.create_def(id2, DefPathData::Use, use_tree.prefix.span);
             }
             UseTreeKind::Glob => (),
             UseTreeKind::Nested(..) => {}

compiler/rustc_symbol_mangling/src/v0.rs

@@ -788,7 +788,8 @@ impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
 
             // These should never show up as `path_append` arguments.
             DefPathData::CrateRoot
-            | DefPathData::Misc
+            | DefPathData::Use
+            | DefPathData::GlobalAsm
             | DefPathData::Impl
             | DefPathData::MacroNs(_)
             | DefPathData::LifetimeNs(_) => {

src/test/mir-opt/inline/cycle.g.Inline.diff

@@ -4,22 +4,55 @@
   fn g() -> () {
       let mut _0: ();                      // return place in scope 0 at $DIR/cycle.rs:11:8: 11:8
       let _1: ();                          // in scope 0 at $DIR/cycle.rs:12:5: 12:12
++     let mut _2: fn() {main};             // in scope 0 at $DIR/cycle.rs:12:5: 12:12
++     let mut _5: ();                      // in scope 0 at $DIR/cycle.rs:6:5: 6:8
++     scope 1 (inlined f::<fn() {main}>) { // at $DIR/cycle.rs:12:5: 12:12
++         debug g => _2;                   // in scope 1 at $DIR/cycle.rs:5:6: 5:7
++         let _3: ();                      // in scope 1 at $DIR/cycle.rs:6:5: 6:8
++         let mut _4: &fn() {main};        // in scope 1 at $DIR/cycle.rs:6:5: 6:6
++         scope 2 (inlined <fn() {main} as Fn<()>>::call - shim(fn() {main})) { // at $DIR/cycle.rs:6:5: 6:8
++         }
++     }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/cycle.rs:12:5: 12:12
-          _1 = f::<fn() {main}>(main) -> bb1; // scope 0 at $DIR/cycle.rs:12:5: 12:12
+-         _1 = f::<fn() {main}>(main) -> bb1; // scope 0 at $DIR/cycle.rs:12:5: 12:12
-                                           // mir::Constant
++         StorageLive(_2);                 // scope 0 at $DIR/cycle.rs:12:5: 12:12
-                                           // + span: $DIR/cycle.rs:12:5: 12:6
++         _2 = main;                       // scope 0 at $DIR/cycle.rs:12:5: 12:12
-                                           // + literal: Const { ty: fn(fn() {main}) {f::<fn() {main}>}, val: Value(Scalar(<ZST>)) }
                                            // mir::Constant
+-                                          // + span: $DIR/cycle.rs:12:5: 12:6
+-                                          // + literal: Const { ty: fn(fn() {main}) {f::<fn() {main}>}, val: Value(Scalar(<ZST>)) }
+-                                          // mir::Constant
                                            // + span: $DIR/cycle.rs:12:7: 12:11
                                            // + literal: Const { ty: fn() {main}, val: Value(Scalar(<ZST>)) }
++         StorageLive(_3);                 // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         StorageLive(_4);                 // scope 1 at $DIR/cycle.rs:6:5: 6:6
++         _4 = &_2;                        // scope 1 at $DIR/cycle.rs:6:5: 6:6
++         StorageLive(_5);                 // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         _5 = const ();                   // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         _3 = move (*_4)() -> [return: bb4, unwind: bb2]; // scope 2 at $SRC_DIR/core/src/ops/function.rs:LL:COL
       }
   
       bb1: {
++         StorageDead(_2);                 // scope 0 at $DIR/cycle.rs:12:5: 12:12
           StorageDead(_1);                 // scope 0 at $DIR/cycle.rs:12:12: 12:13
           _0 = const ();                   // scope 0 at $DIR/cycle.rs:11:8: 13:2
           return;                          // scope 0 at $DIR/cycle.rs:13:2: 13:2
++     }
++ 
++     bb2 (cleanup): {
++         drop(_2) -> bb3;                 // scope 1 at $DIR/cycle.rs:7:1: 7:2
++     }
++ 
++     bb3 (cleanup): {
++         resume;                          // scope 1 at $DIR/cycle.rs:5:1: 7:2
++     }
++ 
++     bb4: {
++         StorageDead(_5);                 // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         StorageDead(_4);                 // scope 1 at $DIR/cycle.rs:6:7: 6:8
++         StorageDead(_3);                 // scope 1 at $DIR/cycle.rs:6:8: 6:9
++         drop(_2) -> bb1;                 // scope 1 at $DIR/cycle.rs:7:1: 7:2
       }
   }
   

src/test/mir-opt/inline/cycle.main.Inline.diff

@@ -4,22 +4,72 @@
   fn main() -> () {
       let mut _0: ();                      // return place in scope 0 at $DIR/cycle.rs:16:11: 16:11
       let _1: ();                          // in scope 0 at $DIR/cycle.rs:17:5: 17:9
++     let mut _2: fn() {g};                // in scope 0 at $DIR/cycle.rs:17:5: 17:9
++     let mut _5: ();                      // in scope 0 at $DIR/cycle.rs:6:5: 6:8
++     scope 1 (inlined f::<fn() {g}>) {    // at $DIR/cycle.rs:17:5: 17:9
++         debug g => _2;                   // in scope 1 at $DIR/cycle.rs:5:6: 5:7
++         let _3: ();                      // in scope 1 at $DIR/cycle.rs:6:5: 6:8
++         let mut _4: &fn() {g};           // in scope 1 at $DIR/cycle.rs:6:5: 6:6
++         scope 2 (inlined <fn() {g} as Fn<()>>::call - shim(fn() {g})) { // at $DIR/cycle.rs:6:5: 6:8
++             scope 3 (inlined g) {        // at $SRC_DIR/core/src/ops/function.rs:LL:COL
++                 let mut _6: fn() {main}; // in scope 3 at $DIR/cycle.rs:12:5: 12:12
++                 scope 4 (inlined f::<fn() {main}>) { // at $DIR/cycle.rs:12:5: 12:12
++                     debug g => _6;       // in scope 4 at $DIR/cycle.rs:5:6: 5:7
++                     let _7: ();          // in scope 4 at $DIR/cycle.rs:6:5: 6:8
++                     let mut _8: &fn() {main}; // in scope 4 at $DIR/cycle.rs:6:5: 6:6
++                     scope 5 (inlined <fn() {main} as Fn<()>>::call - shim(fn() {main})) { // at $DIR/cycle.rs:6:5: 6:8
++                     }
++                 }
++             }
++         }
++     }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/cycle.rs:17:5: 17:9
-          _1 = f::<fn() {g}>(g) -> bb1;    // scope 0 at $DIR/cycle.rs:17:5: 17:9
+-         _1 = f::<fn() {g}>(g) -> bb1;    // scope 0 at $DIR/cycle.rs:17:5: 17:9
-                                           // mir::Constant
++         StorageLive(_2);                 // scope 0 at $DIR/cycle.rs:17:5: 17:9
-                                           // + span: $DIR/cycle.rs:17:5: 17:6
++         _2 = g;                          // scope 0 at $DIR/cycle.rs:17:5: 17:9
-                                           // + literal: Const { ty: fn(fn() {g}) {f::<fn() {g}>}, val: Value(Scalar(<ZST>)) }
                                            // mir::Constant
+-                                          // + span: $DIR/cycle.rs:17:5: 17:6
+-                                          // + literal: Const { ty: fn(fn() {g}) {f::<fn() {g}>}, val: Value(Scalar(<ZST>)) }
+-                                          // mir::Constant
                                            // + span: $DIR/cycle.rs:17:7: 17:8
                                            // + literal: Const { ty: fn() {g}, val: Value(Scalar(<ZST>)) }
++         StorageLive(_3);                 // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         StorageLive(_4);                 // scope 1 at $DIR/cycle.rs:6:5: 6:6
++         _4 = &_2;                        // scope 1 at $DIR/cycle.rs:6:5: 6:6
++         StorageLive(_5);                 // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         _5 = const ();                   // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         StorageLive(_6);                 // scope 3 at $DIR/cycle.rs:12:5: 12:12
++         StorageLive(_7);                 // scope 4 at $DIR/cycle.rs:6:5: 6:8
++         StorageLive(_8);                 // scope 4 at $DIR/cycle.rs:6:5: 6:6
++         _8 = &_6;                        // scope 4 at $DIR/cycle.rs:6:5: 6:6
++         _7 = move (*_8)() -> [return: bb4, unwind: bb2]; // scope 5 at $SRC_DIR/core/src/ops/function.rs:LL:COL
       }
   
       bb1: {
++         StorageDead(_2);                 // scope 0 at $DIR/cycle.rs:17:5: 17:9
           StorageDead(_1);                 // scope 0 at $DIR/cycle.rs:17:9: 17:10
           _0 = const ();                   // scope 0 at $DIR/cycle.rs:16:11: 18:2
           return;                          // scope 0 at $DIR/cycle.rs:18:2: 18:2
++     }
++ 
++     bb2 (cleanup): {
++         drop(_2) -> bb3;                 // scope 1 at $DIR/cycle.rs:7:1: 7:2
++     }
++ 
++     bb3 (cleanup): {
++         resume;                          // scope 1 at $DIR/cycle.rs:5:1: 7:2
++     }
++ 
++     bb4: {
++         StorageDead(_8);                 // scope 4 at $DIR/cycle.rs:6:7: 6:8
++         StorageDead(_7);                 // scope 4 at $DIR/cycle.rs:6:8: 6:9
++         StorageDead(_6);                 // scope 3 at $DIR/cycle.rs:12:5: 12:12
++         StorageDead(_5);                 // scope 1 at $DIR/cycle.rs:6:5: 6:8
++         StorageDead(_4);                 // scope 1 at $DIR/cycle.rs:6:7: 6:8
++         StorageDead(_3);                 // scope 1 at $DIR/cycle.rs:6:8: 6:9
++         drop(_2) -> bb1;                 // scope 1 at $DIR/cycle.rs:7:1: 7:2
       }
   }
   

src/test/mir-opt/inline/inline_cycle_generic.main.Inline.diff

@@ -4,20 +4,13 @@
   fn main() -> () {
       let mut _0: ();                      // return place in scope 0 at $DIR/inline-cycle-generic.rs:8:11: 8:11
       let _1: ();                          // in scope 0 at $DIR/inline-cycle-generic.rs:9:5: 9:24
-+     scope 1 (inlined <C as Call>::call) { // at $DIR/inline-cycle-generic.rs:9:5: 9:24
-+         scope 2 (inlined <B<A> as Call>::call) { // at $DIR/inline-cycle-generic.rs:38:9: 38:31
-+         }
-+     }
   
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/inline-cycle-generic.rs:9:5: 9:24
--         _1 = <C as Call>::call() -> bb1; // scope 0 at $DIR/inline-cycle-generic.rs:9:5: 9:24
+          _1 = <C as Call>::call() -> bb1; // scope 0 at $DIR/inline-cycle-generic.rs:9:5: 9:24
-+         _1 = <A as Call>::call() -> bb1; // scope 2 at $DIR/inline-cycle-generic.rs:31:9: 31:28
                                            // mir::Constant
--                                          // + span: $DIR/inline-cycle-generic.rs:9:5: 9:22
+                                           // + span: $DIR/inline-cycle-generic.rs:9:5: 9:22
--                                          // + literal: Const { ty: fn() {<C as Call>::call}, val: Value(Scalar(<ZST>)) }
+                                           // + literal: Const { ty: fn() {<C as Call>::call}, val: Value(Scalar(<ZST>)) }
-+                                          // + span: $DIR/inline-cycle-generic.rs:31:9: 31:26
-+                                          // + literal: Const { ty: fn() {<A as Call>::call}, val: Value(Scalar(<ZST>)) }
       }
   
       bb1: {

src/test/ui/symbol-names/basic.legacy.stderr

@@ -1,10 +1,10 @@
-error: symbol-name(_ZN5basic4main17h87acd86b3a6f1754E)
+error: symbol-name(_ZN5basic4main17hcbad207c0eeb0b3bE)
   --> $DIR/basic.rs:8:1
    |
 LL | #[rustc_symbol_name]
    | ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(basic::main::h87acd86b3a6f1754)
+error: demangling(basic::main::hcbad207c0eeb0b3b)
   --> $DIR/basic.rs:8:1
    |
 LL | #[rustc_symbol_name]

src/test/ui/symbol-names/issue-60925.legacy.stderr

@@ -1,10 +1,10 @@
-error: symbol-name(_ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo17h8d22952c45e20d65E)
+error: symbol-name(_ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo17h2f2efcf580c9b1eeE)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: demangling(issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo::h8d22952c45e20d65)
+error: demangling(issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo::h2f2efcf580c9b1ee)
   --> $DIR/issue-60925.rs:21:9
    |
 LL |         #[rustc_symbol_name]

src/test/ui/traits/object/enforce-supertrait-projection.rs

@@ -7,7 +7,7 @@ trait Trait: SuperTrait<A = <Self as SuperTrait>::B> {}
 
 fn transmute<A, B>(x: A) -> B {
     foo::<A, B, dyn Trait<A = A, B = B>>(x)
-    //~^ ERROR type mismatch resolving `<dyn Trait<A = A, B = B> as SuperTrait>::A == B`
+    //~^ ERROR type mismatch resolving `<dyn Trait<B = B, A = A> as SuperTrait>::A == B`
 }
 
 fn foo<A, B, T: ?Sized>(x: T::A) -> B

src/test/ui/traits/object/enforce-supertrait-projection.stderr

@@ -1,4 +1,4 @@
-error[E0271]: type mismatch resolving `<dyn Trait<A = A, B = B> as SuperTrait>::A == B`
+error[E0271]: type mismatch resolving `<dyn Trait<B = B, A = A> as SuperTrait>::A == B`
   --> $DIR/enforce-supertrait-projection.rs:9:5
    |
 LL | fn transmute<A, B>(x: A) -> B {