[gcc r14-7861] gccrs: fix ICE when we have unimplemented/invalid trait items

[gcc r14-7861] gccrs: fix ICE when we have unimplemented/invalid trait items

[Arthur Cohen]

https://gcc.gnu.org/g:46a5df00ab59a9bb816f5865efb9196e31bc18c6

commit r14-7861-g46a5df00ab59a9bb816f5865efb9196e31bc18c6
Author: Philip Herron <herron.philip@googlemail.com>
Date:   Sat Jul 29 17:33:47 2023 +0100

    gccrs: fix ICE when we have unimplemented/invalid trait items
    
    When the resulting trait item is in an error state this means the
    underlying fields will be null.
    
    Fixes #2478
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-hir-type-check-item.cc: add is_error check
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/non_member_const.rs: add missing error message
            * rust/compile/issue-2478.rs: New test.
    
    Signed-off-by: Philip Herron <herron.philip@googlemail.com>

Diff:
---
 gcc/rust/typecheck/rust-hir-type-check-item.cc |  3 ++-
 gcc/testsuite/rust/compile/issue-2478.rs       | 16 ++++++++++++++++
 gcc/testsuite/rust/compile/non_member_const.rs |  6 ++----
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/gcc/rust/typecheck/rust-hir-type-check-item.cc b/gcc/rust/typecheck/rust-hir-type-check-item.cc
index 98c5c1a4fec..b329ac13179 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-item.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-item.cc
@@ -615,7 +615,8 @@ TypeCheckItem::validate_trait_impl_block (
 						   impl_item.get (), self,
 						   specified_bound,
 						   substitutions);
-	  trait_item_refs.push_back (trait_item_ref.get_raw_item ());
+	  if (!trait_item_ref.is_error ())
+	    trait_item_refs.push_back (trait_item_ref.get_raw_item ());
 	}
     }
 
diff --git a/gcc/testsuite/rust/compile/issue-2478.rs b/gcc/testsuite/rust/compile/issue-2478.rs
new file mode 100644
index 00000000000..7fe4e2d2a94
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-2478.rs
@@ -0,0 +1,16 @@
+#[lang = "sized"]
+pub trait Sized {}
+
+struct Bar;
+
+trait Foo {
+    const N: u32;
+
+    fn M();
+}
+
+impl Foo for Bar {
+    // { dg-error "missing N, M in implementation of trait .Foo." "" { target *-*-* } .-1 }
+    fn N() {}
+    // { dg-error "method .N. is not a member of trait .Foo." "" { target *-*-* } .-1 }
+}
diff --git a/gcc/testsuite/rust/compile/non_member_const.rs b/gcc/testsuite/rust/compile/non_member_const.rs
index b9740025266..5812db29e03 100644
--- a/gcc/testsuite/rust/compile/non_member_const.rs
+++ b/gcc/testsuite/rust/compile/non_member_const.rs
@@ -7,9 +7,7 @@ trait Foo {
 
 struct Bar;
 
-impl Foo for Bar {
+impl Foo for Bar {// { dg-error "missing N in implementation of trait .Foo." }
     const N : u32 = 0; // { dg-error "item .N. is an associated const, which does not match its trait .Foo." }
-    // error: item `N` is an associated const, which doesn't match its
-    //        trait `<Bar as Foo>`
 }
-}
\ No newline at end of file
+}