[COMMITTED 090/144] gccrs: rust fix ICE when hir lowering qualified path expressions without an as

[arthur . cohen]

From: Philip Herron <herron.phi...@googlemail.com>

Qualified path expressions usually are <X as Y>::... but the as is optional
this adds the extra checking in hir lowering to not hit that nullptr.

Fixes #3082

gcc/rust/ChangeLog:

        * hir/rust-ast-lower-type.cc (ASTLowerQualifiedPathInType::visit):
        check for valid as segment

gcc/testsuite/ChangeLog:

        * rust/compile/nr2/exclude: nr2 cant handle this
        * rust/compile/issue-3082.rs: New test.

Signed-off-by: Philip Herron <herron.phi...@googlemail.com>
---
 gcc/rust/hir/rust-ast-lower-type.cc      | 11 +++++++++--
 gcc/testsuite/rust/compile/issue-3082.rs |  9 +++++++++
 gcc/testsuite/rust/compile/nr2/exclude   |  1 +
 3 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/rust/compile/issue-3082.rs

diff --git a/gcc/rust/hir/rust-ast-lower-type.cc 
b/gcc/rust/hir/rust-ast-lower-type.cc
index 883af4adb47..7d6ac5ddffa 100644
--- a/gcc/rust/hir/rust-ast-lower-type.cc
+++ b/gcc/rust/hir/rust-ast-lower-type.cc
@@ -145,8 +145,15 @@ ASTLowerQualifiedPathInType::visit 
(AST::QualifiedPathInType &path)
 
   HIR::Type *qual_type
     = ASTLoweringType::translate (path.get_qualified_path_type ().get_type ());
-  HIR::TypePath *qual_trait = ASTLowerTypePath::translate (
-    path.get_qualified_path_type ().get_as_type_path ());
+
+  HIR::TypePath *qual_trait = nullptr;
+  if (!path.get_qualified_path_type ().is_error ())
+    {
+      AST::QualifiedPathType &qualifier = path.get_qualified_path_type ();
+      if (qualifier.has_as_clause ())
+       qual_trait
+         = ASTLowerTypePath::translate (qualifier.get_as_type_path ());
+    }
 
   HIR::QualifiedPathType qual_path_type (
     qual_mappings, std::unique_ptr<HIR::Type> (qual_type),
diff --git a/gcc/testsuite/rust/compile/issue-3082.rs 
b/gcc/testsuite/rust/compile/issue-3082.rs
new file mode 100644
index 00000000000..4b873955dde
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3082.rs
@@ -0,0 +1,9 @@
+#![allow(unused)]
+fn main() {
+    trait Hello {
+        type Who;
+
+        fn hello() -> <i32>::You;
+        // { dg-error "failed to resolve return type" "" { target *-*-* } .-1 }
+    }
+}
diff --git a/gcc/testsuite/rust/compile/nr2/exclude 
b/gcc/testsuite/rust/compile/nr2/exclude
index 5f5863bde87..3412617f7eb 100644
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -277,3 +277,4 @@ dropck_eyepatch_feature_gate.rs
 inline_asm_parse_output_operand.rs
 issue-3030.rs
 issue-3035.rs
+issue-3082.rs
\ No newline at end of file
-- 
2.45.2