Rollup merge of #101185 - compiler-errors:tweak-wf-locs, r=davidtwco

Tweak `WellFormedLoc`s a bit

Gives a bit tighter spans in returns and generic ty defaults

13 files changed, 52 insertions, 33 deletions

diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
index ce42647c837..ba42453bd60 100644
--- a/compiler/rustc_typeck/src/check/wfcheck.rs
+++ b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -1262,7 +1262,11 @@ fn check_impl<'tcx>(
             }
             None => {
                 let self_ty = tcx.type_of(item.def_id);
-                let self_ty = wfcx.normalize(item.span, None, self_ty);
+                let self_ty = wfcx.normalize(
+                    item.span,
+                    Some(WellFormedLoc::Ty(item.hir_id().expect_owner())),
+                    self_ty,
+                );
                 wfcx.register_wf_obligation(
                     ast_self_ty.span,
                     Some(WellFormedLoc::Ty(item.hir_id().expect_owner())),
@@ -1307,7 +1311,11 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
                     // parameter includes another (e.g., `<T, U = T>`). In those cases, we can't
                     // be sure if it will error or not as user might always specify the other.
                     if !ty.needs_subst() {
-                        wfcx.register_wf_obligation(tcx.def_span(param.def_id), None, ty.into());
+                        wfcx.register_wf_obligation(
+                            tcx.def_span(param.def_id),
+                            Some(WellFormedLoc::Ty(param.def_id.expect_local())),
+                            ty.into(),
+                        );
                     }
                 }
             }
@@ -1512,7 +1520,14 @@ fn check_fn_or_method<'tcx>(
         );
     }
 
-    wfcx.register_wf_obligation(hir_decl.output.span(), None, sig.output().into());
+    wfcx.register_wf_obligation(
+        hir_decl.output.span(),
+        Some(WellFormedLoc::Param {
+            function: def_id,
+            param_idx: sig.inputs().len().try_into().unwrap(),
+        }),
+        sig.output().into(),
+    );
 
     check_where_clauses(wfcx, span, def_id);
 }
diff --git a/compiler/rustc_typeck/src/hir_wf_check.rs b/compiler/rustc_typeck/src/hir_wf_check.rs
index fd9715e6ca3..7b080dc2942 100644
--- a/compiler/rustc_typeck/src/hir_wf_check.rs
+++ b/compiler/rustc_typeck/src/hir_wf_check.rs
@@ -140,6 +140,10 @@ fn diagnostic_hir_wf_check<'tcx>(
             hir::Node::ForeignItem(ForeignItem {
                 kind: ForeignItemKind::Static(ty, _), ..
             }) => Some(*ty),
+            hir::Node::GenericParam(hir::GenericParam {
+                kind: hir::GenericParamKind::Type { default: Some(ty), .. },
+                ..
+            }) => Some(*ty),
             ref node => bug!("Unexpected node {:?}", node),
         },
         WellFormedLoc::Param { function: _, param_idx } => {
diff --git a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
index 72cb4cc843c..d76c697fe73 100644
--- a/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
+++ b/src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
@@ -13,10 +13,10 @@ LL | trait NonObjectSafe1: Sized {}
    |       this trait cannot be made into an object...
 
 error[E0038]: the trait `NonObjectSafe2` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:22:36
+  --> $DIR/feature-gate-object_safe_for_dispatch.rs:22:45
    |
 LL | fn return_non_object_safe_ref() -> &'static dyn NonObjectSafe2 {
-   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ `NonObjectSafe2` cannot be made into an object
+   |                                             ^^^^^^^^^^^^^^^^^^ `NonObjectSafe2` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:7:8
@@ -50,10 +50,10 @@ LL |     fn foo<T>(&self);
    = help: consider moving `foo` to another trait
 
 error[E0038]: the trait `NonObjectSafe4` cannot be made into an object
-  --> $DIR/feature-gate-object_safe_for_dispatch.rs:31:35
+  --> $DIR/feature-gate-object_safe_for_dispatch.rs:31:47
    |
 LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn NonObjectSafe4> {
-   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `NonObjectSafe4` cannot be made into an object
+   |                                               ^^^^^^^^^^^^^^^^^^ `NonObjectSafe4` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/feature-gate-object_safe_for_dispatch.rs:15:22
diff --git a/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr b/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr
index 365ecd9fcfa..687dbe65e6c 100644
--- a/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr
+++ b/src/test/ui/impl-trait/object-unsafe-trait-in-return-position-dyn-trait.stderr
@@ -21,10 +21,10 @@ LL |     fn foo() -> Self where Self: Sized;
    |                      +++++++++++++++++
 
 error[E0038]: the trait `NotObjectSafe` cannot be made into an object
-  --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:28:13
+  --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:28:17
    |
 LL | fn cat() -> Box<dyn NotObjectSafe> {
-   |             ^^^^^^^^^^^^^^^^^^^^^^ `NotObjectSafe` cannot be made into an object
+   |                 ^^^^^^^^^^^^^^^^^ `NotObjectSafe` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-unsafe-trait-in-return-position-dyn-trait.rs:3:8
diff --git a/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr b/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr
index 9dd144fee24..5f94c9284ea 100644
--- a/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-associated-consts.curr.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `Bar` cannot be made into an object
-  --> $DIR/object-safety-associated-consts.rs:12:30
+  --> $DIR/object-safety-associated-consts.rs:12:31
    |
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
-   |                              ^^^^^^^^ `Bar` cannot be made into an object
+   |                               ^^^^^^^ `Bar` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-associated-consts.rs:9:11
diff --git a/src/test/ui/object-safety/object-safety-bounds.stderr b/src/test/ui/object-safety/object-safety-bounds.stderr
index 89c4f8ced79..29ffb544842 100644
--- a/src/test/ui/object-safety/object-safety-bounds.stderr
+++ b/src/test/ui/object-safety/object-safety-bounds.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `X` cannot be made into an object
-  --> $DIR/object-safety-bounds.rs:7:11
+  --> $DIR/object-safety-bounds.rs:7:15
    |
 LL | fn f() -> Box<dyn X<U = u32>> {
-   |           ^^^^^^^^^^^^^^^^^^^ `X` cannot be made into an object
+   |               ^^^^^^^^^^^^^^ `X` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-bounds.rs:4:13
diff --git a/src/test/ui/object-safety/object-safety-generics.curr.stderr b/src/test/ui/object-safety/object-safety-generics.curr.stderr
index 345950f1ae6..45810375263 100644
--- a/src/test/ui/object-safety/object-safety-generics.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-generics.curr.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `Bar` cannot be made into an object
-  --> $DIR/object-safety-generics.rs:18:30
+  --> $DIR/object-safety-generics.rs:18:31
    |
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
-   |                              ^^^^^^^^ `Bar` cannot be made into an object
+   |                               ^^^^^^^ `Bar` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-generics.rs:10:8
@@ -14,10 +14,10 @@ LL |     fn bar<T>(&self, t: T);
    = help: consider moving `bar` to another trait
 
 error[E0038]: the trait `Bar` cannot be made into an object
-  --> $DIR/object-safety-generics.rs:24:39
+  --> $DIR/object-safety-generics.rs:24:40
    |
 LL | fn make_bar_explicit<T:Bar>(t: &T) -> &dyn Bar {
-   |                                       ^^^^^^^^ `Bar` cannot be made into an object
+   |                                        ^^^^^^^ `Bar` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-generics.rs:10:8
diff --git a/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr b/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr
index f91c9b98560..de430a89bf8 100644
--- a/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-mentions-Self.curr.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `Bar` cannot be made into an object
-  --> $DIR/object-safety-mentions-Self.rs:22:30
+  --> $DIR/object-safety-mentions-Self.rs:22:31
    |
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
-   |                              ^^^^^^^^ `Bar` cannot be made into an object
+   |                               ^^^^^^^ `Bar` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-mentions-Self.rs:11:22
@@ -14,10 +14,10 @@ LL |     fn bar(&self, x: &Self);
    = help: consider moving `bar` to another trait
 
 error[E0038]: the trait `Baz` cannot be made into an object
-  --> $DIR/object-safety-mentions-Self.rs:28:30
+  --> $DIR/object-safety-mentions-Self.rs:28:31
    |
 LL | fn make_baz<T:Baz>(t: &T) -> &dyn Baz {
-   |                              ^^^^^^^^ `Baz` cannot be made into an object
+   |                               ^^^^^^^ `Baz` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-mentions-Self.rs:15:22
diff --git a/src/test/ui/object-safety/object-safety-no-static.curr.stderr b/src/test/ui/object-safety/object-safety-no-static.curr.stderr
index bd8cf4e30f7..1b025229e54 100644
--- a/src/test/ui/object-safety/object-safety-no-static.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-no-static.curr.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `Foo` cannot be made into an object
-  --> $DIR/object-safety-no-static.rs:12:18
+  --> $DIR/object-safety-no-static.rs:12:22
    |
 LL | fn diverges() -> Box<dyn Foo> {
-   |                  ^^^^^^^^^^^^ `Foo` cannot be made into an object
+   |                      ^^^^^^^ `Foo` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-no-static.rs:9:8
diff --git a/src/test/ui/object-safety/object-safety-sized-2.curr.stderr b/src/test/ui/object-safety/object-safety-sized-2.curr.stderr
index 71236c8e384..b019264128e 100644
--- a/src/test/ui/object-safety/object-safety-sized-2.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-sized-2.curr.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `Bar` cannot be made into an object
-  --> $DIR/object-safety-sized-2.rs:14:30
+  --> $DIR/object-safety-sized-2.rs:14:31
    |
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
-   |                              ^^^^^^^^ `Bar` cannot be made into an object
+   |                               ^^^^^^^ `Bar` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-sized-2.rs:9:18
diff --git a/src/test/ui/object-safety/object-safety-sized.curr.stderr b/src/test/ui/object-safety/object-safety-sized.curr.stderr
index 94b06ee934d..97481312142 100644
--- a/src/test/ui/object-safety/object-safety-sized.curr.stderr
+++ b/src/test/ui/object-safety/object-safety-sized.curr.stderr
@@ -1,8 +1,8 @@
 error[E0038]: the trait `Bar` cannot be made into an object
-  --> $DIR/object-safety-sized.rs:12:30
+  --> $DIR/object-safety-sized.rs:12:31
    |
 LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
-   |                              ^^^^^^^^ `Bar` cannot be made into an object
+   |                               ^^^^^^^ `Bar` cannot be made into an object
    |
 note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
   --> $DIR/object-safety-sized.rs:8:13
diff --git a/src/test/ui/type/type-check-defaults.stderr b/src/test/ui/type/type-check-defaults.stderr
index 56a9b5317f7..cf77c057d46 100644
--- a/src/test/ui/type/type-check-defaults.stderr
+++ b/src/test/ui/type/type-check-defaults.stderr
@@ -1,8 +1,8 @@
 error[E0277]: a value of type `i32` cannot be built from an iterator over elements of type `i32`
-  --> $DIR/type-check-defaults.rs:6:19
+  --> $DIR/type-check-defaults.rs:6:23
    |
 LL | struct WellFormed<Z = Foo<i32, i32>>(Z);
-   |                   ^^^^^^^^^^^^^^^^^ value of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
+   |                       ^^^^^^^^^^^^^ value of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
    |
    = help: the trait `FromIterator<i32>` is not implemented for `i32`
 note: required by a bound in `Foo`
@@ -12,10 +12,10 @@ LL | struct Foo<T, U: FromIterator<T>>(T, U);
    |                  ^^^^^^^^^^^^^^^ required by this bound in `Foo`
 
 error[E0277]: a value of type `i32` cannot be built from an iterator over elements of type `i32`
-  --> $DIR/type-check-defaults.rs:8:27
+  --> $DIR/type-check-defaults.rs:8:38
    |
 LL | struct WellFormedNoBounds<Z:?Sized = Foo<i32, i32>>(Z);
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^ value of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
+   |                                      ^^^^^^^^^^^^^ value of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
    |
    = help: the trait `FromIterator<i32>` is not implemented for `i32`
 note: required by a bound in `Foo`
diff --git a/src/test/ui/wf/wf-trait-fn-ret.stderr b/src/test/ui/wf/wf-trait-fn-ret.stderr
index a59ba3400a4..9bd3cc7711b 100644
--- a/src/test/ui/wf/wf-trait-fn-ret.stderr
+++ b/src/test/ui/wf/wf-trait-fn-ret.stderr
@@ -1,8 +1,8 @@
 error[E0277]: the trait bound `Self: Eq` is not satisfied
-  --> $DIR/wf-trait-fn-ret.rs:10:22
+  --> $DIR/wf-trait-fn-ret.rs:10:23
    |
 LL |     fn bar(&self) -> &Bar<Self>;
-   |                      ^^^^^^^^^^ the trait `Eq` is not implemented for `Self`
+   |                       ^^^^^^^^^ the trait `Eq` is not implemented for `Self`
    |
 note: required by a bound in `Bar`
   --> $DIR/wf-trait-fn-ret.rs:7:14