Compute a more precise span for opaque type impls

11 files changed, 51 insertions, 22 deletions

diff --git a/compiler/rustc_typeck/src/coherence/orphan.rs b/compiler/rustc_typeck/src/coherence/orphan.rs
index 564c3d31368..76c41dedf0a 100644
--- a/compiler/rustc_typeck/src/coherence/orphan.rs
+++ b/compiler/rustc_typeck/src/coherence/orphan.rs
@@ -7,6 +7,7 @@ use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_index::bit_set::GrowableBitSet;
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::subst::{GenericArg, InternalSubsts};
 use rustc_middle::ty::{self, ImplPolarity, Ty, TyCtxt, TypeFoldable, TypeVisitor};
 use rustc_session::lint;
@@ -144,13 +145,41 @@ fn orphan_check_impl(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), ErrorGua
     // Ensure no opaque types are present in this impl header. See issues #76202 and #86411 for examples,
     // and #84660 where it would otherwise allow unsoundness.
     if trait_ref.has_opaque_types() {
+        trace!("{:#?}", item);
         for ty in trait_ref.substs {
             for ty in ty.walk() {
                 let ty::subst::GenericArgKind::Type(ty) = ty.unpack() else { continue };
-                let ty::Opaque(def_id, _) = ty.kind() else { continue };
+                let ty::Opaque(def_id, _) = *ty.kind() else { continue };
+                trace!(?def_id);
+                struct SpanFinder<'tcx> {
+                    sp: Span,
+                    def_id: DefId,
+                    tcx: TyCtxt<'tcx>,
+                }
+                impl<'v, 'tcx> hir::intravisit::Visitor<'v> for SpanFinder<'tcx> {
+                    #[instrument(level = "trace", skip(self, _id))]
+                    fn visit_path(&mut self, path: &'v hir::Path<'v>, _id: hir::HirId) {
+                        if let hir::def::Res::Def(hir::def::DefKind::TyAlias, def_id) = path.res {
+                            for arg in self.tcx.type_of(def_id).walk() {
+                                if let GenericArgKind::Type(ty) = arg.unpack() {
+                                    if let ty::Opaque(def_id, _) = *ty.kind() {
+                                        if def_id == self.def_id {
+                                            self.sp = path.span;
+                                            return;
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                        hir::intravisit::walk_path(self, path)
+                    }
+                }
+
+                let mut visitor = SpanFinder { sp, def_id, tcx };
+                hir::intravisit::walk_item(&mut visitor, item);
                 let reported = tcx
                     .sess
-                    .struct_span_err(sp, "cannot implement trait on type alias impl trait")
+                    .struct_span_err(visitor.sp, "cannot implement trait on type alias impl trait")
                     .span_note(tcx.def_span(def_id), "type alias impl trait defined here")
                     .emit();
                 return Err(reported);
diff --git a/src/test/ui/impl-trait/auto-trait.stderr b/src/test/ui/impl-trait/auto-trait.stderr
index 9171cfca5b1..3b360f492b7 100644
--- a/src/test/ui/impl-trait/auto-trait.stderr
+++ b/src/test/ui/impl-trait/auto-trait.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/auto-trait.rs:21:1
+  --> $DIR/auto-trait.rs:21:25
    |
 LL | impl AnotherTrait for D<OpaqueType> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                         ^^^^^^^^^^
    |
 note: type alias impl trait defined here
   --> $DIR/auto-trait.rs:7:19
diff --git a/src/test/ui/impl-trait/negative-reasoning.stderr b/src/test/ui/impl-trait/negative-reasoning.stderr
index 1a7233bca5c..98f9fbd8fef 100644
--- a/src/test/ui/impl-trait/negative-reasoning.stderr
+++ b/src/test/ui/impl-trait/negative-reasoning.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/negative-reasoning.rs:19:1
+  --> $DIR/negative-reasoning.rs:19:25
    |
 LL | impl AnotherTrait for D<OpaqueType> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                         ^^^^^^^^^^
    |
 note: type alias impl trait defined here
   --> $DIR/negative-reasoning.rs:7:19
diff --git a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr
index 4e8d4cce0a1..2ef1697ba34 100644
--- a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr
+++ b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:7:1
+  --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:7:17
    |
 LL | impl PartialEq<(Foo, i32)> for Bar {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                 ^^^
    |
 note: type alias impl trait defined here
   --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:3:12
diff --git a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr
index ccb0bc0a366..6cd63dcf81c 100644
--- a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr
+++ b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:20:5
+  --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:20:21
    |
 LL |     impl PartialEq<(Foo, i32)> for Bar {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                     ^^^
    |
 note: type alias impl trait defined here
   --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:16:16
diff --git a/src/test/ui/traits/alias/issue-83613.stderr b/src/test/ui/traits/alias/issue-83613.stderr
index 4f19e6607c8..bbc240b6aec 100644
--- a/src/test/ui/traits/alias/issue-83613.stderr
+++ b/src/test/ui/traits/alias/issue-83613.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/issue-83613.rs:10:1
+  --> $DIR/issue-83613.rs:10:23
    |
 LL | impl AnotherTrait for OpaqueType {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                       ^^^^^^^^^^
    |
 note: type alias impl trait defined here
   --> $DIR/issue-83613.rs:4:19
diff --git a/src/test/ui/type-alias-impl-trait/issue-65384.stderr b/src/test/ui/type-alias-impl-trait/issue-65384.stderr
index 27680f0ad75..41bcea27e1f 100644
--- a/src/test/ui/type-alias-impl-trait/issue-65384.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-65384.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/issue-65384.rs:10:1
+  --> $DIR/issue-65384.rs:10:18
    |
 LL | impl MyTrait for Bar {}
-   | ^^^^^^^^^^^^^^^^^^^^
+   |                  ^^^
    |
 note: type alias impl trait defined here
   --> $DIR/issue-65384.rs:8:12
diff --git a/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr b/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr
index 8689ee53660..2d4a6854a92 100644
--- a/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/issue-76202-trait-impl-for-tait.rs:16:1
+  --> $DIR/issue-76202-trait-impl-for-tait.rs:16:15
    |
 LL | impl Test for F {
-   | ^^^^^^^^^^^^^^^
+   |               ^
    |
 note: type alias impl trait defined here
   --> $DIR/issue-76202-trait-impl-for-tait.rs:9:10
diff --git a/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr b/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr
index 1b8eee40717..bb70d07be59 100644
--- a/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/issue-84660-trait-impl-for-tait.rs:15:1
+  --> $DIR/issue-84660-trait-impl-for-tait.rs:15:15
    |
 LL | impl TraitArg<Bar> for () {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |               ^^^
    |
 note: type alias impl trait defined here
   --> $DIR/issue-84660-trait-impl-for-tait.rs:8:12
diff --git a/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr b/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr
index b1128d830f9..f2d600fb46c 100644
--- a/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr
+++ b/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/issue-84660-unsoundness.rs:16:1
+  --> $DIR/issue-84660-unsoundness.rs:16:21
    |
 LL | impl<In, Out> Trait<Bar, In> for Out {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                     ^^^
    |
 note: type alias impl trait defined here
   --> $DIR/issue-84660-unsoundness.rs:8:12
diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr b/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr
index bf1582639a2..4a3fb16733e 100644
--- a/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr
+++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr
@@ -1,8 +1,8 @@
 error: cannot implement trait on type alias impl trait
-  --> $DIR/nested-tait-inference3.rs:10:1
+  --> $DIR/nested-tait-inference3.rs:10:10
    |
 LL | impl Foo<FooX> for () { }
-   | ^^^^^^^^^^^^^^^^^^^^^
+   |          ^^^^
    |
 note: type alias impl trait defined here
   --> $DIR/nested-tait-inference3.rs:6:13