gccrs: remove bad type checking diagnostic

This was a bad diagnostic added when I was working on slices and iterators
also the name of the function is also bad. This is all about setting up
associated types based on the current context of the bounds assocated with
the associated trait bounds on this function.

The tell tale is that this didnt have an associated rust error code so
this is most definetly not the correct error diagnostic.

Fixes Rust-GCC#3403

gcc/rust/ChangeLog:

	* typecheck/rust-tyty-subst.cc (SubstitutionRef::monomorphize): remove diagnostic

gcc/testsuite/ChangeLog:

	* rust/compile/nr2/exclude: nr2 cant handle this
	* rust/compile/issue-3403.rs: New test.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

3 files changed, 40 insertions, 20 deletions

diff --git a/gcc/rust/typecheck/rust-tyty-subst.cc b/gcc/rust/typecheck/rust-tyty-subst.cc
index 976f6af..26afe1b 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.cc
+++ b/gcc/rust/typecheck/rust-tyty-subst.cc
@@ -934,27 +934,8 @@ SubstitutionRef::monomorphize ()
 	  auto associated
 	    = Resolver::lookup_associated_impl_block (bound, binding,
 						      &ambigious);
-	  if (associated == nullptr && ambigious)
-	    {
-	      // go for the first one? or error out?
-	      auto &mappings = Analysis::Mappings::get ();
-	      const auto &type_param = subst.get_generic_param ();
-	      const auto *trait_ref = bound.get ();
-
-	      rich_location r (line_table, type_param.get_locus ());
-	      r.add_range (bound.get_locus ());
-	      r.add_range (mappings.lookup_location (binding->get_ref ()));
-
-	      rust_error_at (r, "ambiguous type bound for trait %s and type %s",
-			     trait_ref->get_name ().c_str (),
-			     binding->get_name ().c_str ());
-	      return false;
-	    }
-
 	  if (associated != nullptr)
-	    {
-	      associated->setup_associated_types (binding, bound);
-	    }
+	    associated->setup_associated_types (binding, bound);
 	}
     }
 
diff --git a/gcc/testsuite/rust/compile/issue-3403.rs b/gcc/testsuite/rust/compile/issue-3403.rs
new file mode 100644
index 0000000..ced6b4e
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3403.rs
@@ -0,0 +1,38 @@
+pub struct Foo {
+    a: i32,
+    // { dg-warning "field is never read" "" { target *-*-* } .-1 }
+}
+pub struct Bar(i32);
+
+#[lang = "sized"]
+trait Sized {}
+
+pub mod core {
+    pub mod default {
+        pub trait Default: Sized {
+            fn default() -> Self;
+        }
+
+        impl Default for i32 {
+            fn default() -> Self {
+                0
+            }
+        }
+    }
+}
+
+impl ::core::default::Default for Bar {
+    #[inline]
+    fn default() -> Bar {
+        Bar(core::default::Default::default())
+    }
+}
+
+impl ::core::default::Default for Foo {
+    #[inline]
+    fn default() -> Foo {
+        Foo {
+            a: core::default::Default::default(),
+        }
+    }
+}
diff --git a/gcc/testsuite/rust/compile/nr2/exclude b/gcc/testsuite/rust/compile/nr2/exclude
index 5124194..6f6280d 100644
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -123,4 +123,5 @@ derive-default1.rs
 issue-3402-1.rs
 for-loop1.rs
 for-loop2.rs
+issue-3403.rs
 # please don't delete the trailing newline