[gcc/devel/rust/master] Qualified paths can have an optional as clause

[Thomas Schwinge <tschwinge@gcc.gnu.org>]

https://gcc.gnu.org/g:56f503b88a240f1d77c8d6564656bc22269b4842

commit 56f503b88a240f1d77c8d6564656bc22269b4842
Author: Philip Herron <philip.herron@embecosm.com>
Date:   Mon Aug 22 12:43:53 2022 +0100

    Qualified paths can have an optional as clause
    
    Qualified paths can look like <dyn T>::bla with an associated impl block
    for dynamic trait objects. If we implement similar fine grained visitors
    that we use in the HIR this will help solve issues like this where we have
    missing visitors.
    
    Fixes #1249

Diff:
---
 gcc/rust/resolve/rust-ast-resolve-path.cc        |  3 +-
 gcc/rust/resolve/rust-ast-resolve-type.cc        | 21 +++++++++++++
 gcc/rust/resolve/rust-ast-resolve-type.h         |  4 +++
 gcc/rust/typecheck/rust-hir-type-check-path.cc   |  6 ----
 gcc/testsuite/rust/execute/torture/issue-1249.rs | 39 ++++++++++++++++++++++++
 5 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/gcc/rust/resolve/rust-ast-resolve-path.cc b/gcc/rust/resolve/rust-ast-resolve-path.cc
index 27f32aa37ff..b139c6a8720 100644
--- a/gcc/rust/resolve/rust-ast-resolve-path.cc
+++ b/gcc/rust/resolve/rust-ast-resolve-path.cc
@@ -242,8 +242,9 @@ void
 ResolvePath::resolve_path (AST::QualifiedPathInExpression *expr)
 {
   AST::QualifiedPathType &root_segment = expr->get_qualified_path_type ();
-  ResolveType::go (&root_segment.get_as_type_path ());
   ResolveType::go (root_segment.get_type ().get ());
+  if (root_segment.has_as_clause ())
+    ResolveType::go (&root_segment.get_as_type_path ());
 
   for (auto &segment : expr->get_segments ())
     {
diff --git a/gcc/rust/resolve/rust-ast-resolve-type.cc b/gcc/rust/resolve/rust-ast-resolve-type.cc
index a8931ce72c2..6b08613755a 100644
--- a/gcc/rust/resolve/rust-ast-resolve-type.cc
+++ b/gcc/rust/resolve/rust-ast-resolve-type.cc
@@ -477,6 +477,27 @@ ResolveTypeToCanonicalPath::visit (AST::SliceType &type)
     }
 }
 
+void
+ResolveTypeToCanonicalPath::visit (AST::TraitObjectTypeOneBound &type)
+{
+  CanonicalPath path = CanonicalPath::create_empty ();
+  bool ok
+    = ResolveTypeToCanonicalPath::go (&type.get_trait_bound ().get_type_path (),
+				      path);
+  if (ok)
+    {
+      std::string slice_path = "<dyn " + path.get () + ">";
+      result = CanonicalPath::new_seg (type.get_node_id (), slice_path);
+    }
+}
+
+void
+ResolveTypeToCanonicalPath::visit (AST::TraitObjectType &type)
+{
+  // FIXME is this actually allowed? dyn A+B
+  gcc_unreachable ();
+}
+
 ResolveTypeToCanonicalPath::ResolveTypeToCanonicalPath ()
   : ResolverBase (), result (CanonicalPath::create_empty ())
 {}
diff --git a/gcc/rust/resolve/rust-ast-resolve-type.h b/gcc/rust/resolve/rust-ast-resolve-type.h
index b57b5138656..5a71268c0d4 100644
--- a/gcc/rust/resolve/rust-ast-resolve-type.h
+++ b/gcc/rust/resolve/rust-ast-resolve-type.h
@@ -242,6 +242,10 @@ public:
 
   void visit (AST::SliceType &type) override;
 
+  void visit (AST::TraitObjectTypeOneBound &type) override;
+
+  void visit (AST::TraitObjectType &type) override;
+
 private:
   ResolveTypeToCanonicalPath ();
 
diff --git a/gcc/rust/typecheck/rust-hir-type-check-path.cc b/gcc/rust/typecheck/rust-hir-type-check-path.cc
index fd0ca3ea16b..84f3b6ea6e6 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-path.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-path.cc
@@ -34,13 +34,7 @@ TypeCheckExpr::visit (HIR::QualifiedPathInExpression &expr)
 
   if (!qual_path_type.has_as_clause ())
     {
-      // then this is just a normal path-in-expression
       NodeId root_resolved_node_id = UNKNOWN_NODEID;
-      bool ok = resolver->lookup_resolved_type (
-	qual_path_type.get_type ()->get_mappings ().get_nodeid (),
-	&root_resolved_node_id);
-      rust_assert (ok);
-
       resolve_segments (root_resolved_node_id, expr.get_segments (), 0, root,
 			expr.get_mappings (), expr.get_locus ());
       return;
diff --git a/gcc/testsuite/rust/execute/torture/issue-1249.rs b/gcc/testsuite/rust/execute/torture/issue-1249.rs
new file mode 100644
index 00000000000..072204ea877
--- /dev/null
+++ b/gcc/testsuite/rust/execute/torture/issue-1249.rs
@@ -0,0 +1,39 @@
+// { dg-options "-w" }
+// { dg-output "1\n2\n" }
+
+extern "C" {
+    fn printf(s: *const i8, ...);
+}
+
+trait T {
+    fn foo(&self);
+}
+
+impl dyn T {
+    fn bar(&self) {
+        unsafe {
+            let a = "1\n\0";
+            let b = a as *const str;
+            let c = b as *const i8;
+            printf(c);
+        }
+        self.foo()
+    }
+}
+
+struct S;
+impl T for S {
+    fn foo(&self) {
+        unsafe {
+            let a = "2\n\0";
+            let b = a as *const str;
+            let c = b as *const i8;
+            printf(c);
+        }
+    }
+}
+
+pub fn main() -> i32 {
+    <dyn T>::bar(&S);
+    0
+}