Auto merge of #109765 - petrochenkov:encodeless, r=cjgillot

rustc_metadata: Filter encoded data more aggressively using `DefKind`

I focused on data that contains spans, because spans are expensive to encode/decode/hash, but also touched `should_encode_visibility` too.

One incorrect use of impl visibility in diagnostics is also replaced with trait visibility.

2 files changed, 16 insertions, 7 deletions

diff --git a/tests/ui/associated-types/associated-types-in-ambiguous-context.rs b/tests/ui/associated-types/associated-types-in-ambiguous-context.rs
index 51b53908f98..5d6b1b59181 100644
--- a/tests/ui/associated-types/associated-types-in-ambiguous-context.rs
+++ b/tests/ui/associated-types/associated-types-in-ambiguous-context.rs
@@ -1,3 +1,5 @@
+// normalize-stderr-test: "and \d+ other candidates" -> "and N other candidates"
+
 trait Get {
     type Value;
     fn get(&self) -> <Self as Get>::Value;
diff --git a/tests/ui/associated-types/associated-types-in-ambiguous-context.stderr b/tests/ui/associated-types/associated-types-in-ambiguous-context.stderr
index 00856b55df5..1ff6fd4b821 100644
--- a/tests/ui/associated-types/associated-types-in-ambiguous-context.stderr
+++ b/tests/ui/associated-types/associated-types-in-ambiguous-context.stderr
@@ -1,5 +1,5 @@
 error[E0223]: ambiguous associated type
-  --> $DIR/associated-types-in-ambiguous-context.rs:6:36
+  --> $DIR/associated-types-in-ambiguous-context.rs:8:36
    |
 LL | fn get<T:Get,U:Get>(x: T, y: U) -> Get::Value {}
    |                                    ^^^^^^^^^^
@@ -10,30 +10,37 @@ LL | fn get<T:Get,U:Get>(x: T, y: U) -> <Example as Get>::Value {}
    |                                    ~~~~~~~~~~~~~~~~~~~~~~~
 
 error[E0223]: ambiguous associated type
-  --> $DIR/associated-types-in-ambiguous-context.rs:20:17
+  --> $DIR/associated-types-in-ambiguous-context.rs:22:17
    |
 LL | trait Foo where Foo::Assoc: Bar {
    |                 ^^^^^^^^^^ help: use the fully-qualified path: `<Self as Foo>::Assoc`
 
 error[E0223]: ambiguous associated type
-  --> $DIR/associated-types-in-ambiguous-context.rs:25:10
+  --> $DIR/associated-types-in-ambiguous-context.rs:27:10
    |
 LL | type X = std::ops::Deref::Target;
    |          ^^^^^^^^^^^^^^^^^^^^^^^
    |
-help: if there were a type named `Example` that implemented `Deref`, you could use the fully-qualified path
+help: use the fully-qualified path
    |
-LL | type X = <Example as Deref>::Target;
+LL | type X = <CString as Deref>::Target;
    |          ~~~~~~~~~~~~~~~~~~~~~~~~~~
+LL | type X = <IoSlice<'_> as Deref>::Target;
+   |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+LL | type X = <IoSliceMut<'_> as Deref>::Target;
+   |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+LL | type X = <OsString as Deref>::Target;
+   |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+     and N other candidates
 
 error[E0223]: ambiguous associated type
-  --> $DIR/associated-types-in-ambiguous-context.rs:11:23
+  --> $DIR/associated-types-in-ambiguous-context.rs:13:23
    |
 LL |     fn grab(&self) -> Grab::Value;
    |                       ^^^^^^^^^^^ help: use the fully-qualified path: `<Self as Grab>::Value`
 
 error[E0223]: ambiguous associated type
-  --> $DIR/associated-types-in-ambiguous-context.rs:14:22
+  --> $DIR/associated-types-in-ambiguous-context.rs:16:22
    |
 LL |     fn get(&self) -> Get::Value;
    |                      ^^^^^^^^^^