[gcc r15-8419] rust: fix ICE during name resolution for impls on unit-types

[Arthur Cohen via Gcc-cvs]

https://gcc.gnu.org/g:566ae2082c0205f96986dd36f8f01705b7c731b7

commit r15-8419-g566ae2082c0205f96986dd36f8f01705b7c731b7
Author: Philip Herron <herron.phi...@googlemail.com>
Date:   Fri Sep 20 17:38:14 2024 +0100

    rust: fix ICE during name resolution for impls on unit-types
    
    The canonical paths need to support unit-types which are technically a
    TupleType with no fields. This handles this case and adds an unreachable.
    
    Fixes #3036
    
    gcc/rust/ChangeLog:
    
            * resolve/rust-ast-resolve-type.cc 
(ResolveTypeToCanonicalPath::visit): add unit-type catch
            * resolve/rust-ast-resolve-type.h: likewise
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/nr2/exclude: nr2 cant handle this
            * rust/compile/issue-3036.rs: New test.
    
    Signed-off-by: Philip Herron <herron.phi...@googlemail.com>

Diff:
---
 gcc/rust/resolve/rust-ast-resolve-type.cc |  9 +++++++++
 gcc/rust/resolve/rust-ast-resolve-type.h  |  2 ++
 gcc/testsuite/rust/compile/issue-3036.rs  | 14 ++++++++++++++
 gcc/testsuite/rust/compile/nr2/exclude    |  1 +
 4 files changed, 26 insertions(+)

diff --git a/gcc/rust/resolve/rust-ast-resolve-type.cc 
b/gcc/rust/resolve/rust-ast-resolve-type.cc
index cee259cceb45..ec5e8a762a70 100644
--- a/gcc/rust/resolve/rust-ast-resolve-type.cc
+++ b/gcc/rust/resolve/rust-ast-resolve-type.cc
@@ -507,6 +507,15 @@ ResolveTypeToCanonicalPath::visit (AST::NeverType &type)
   result = CanonicalPath::new_seg (type.get_node_id (), "!");
 }
 
+void
+ResolveTypeToCanonicalPath::visit (AST::TupleType &type)
+{
+  if (!type.is_unit_type ())
+    rust_unreachable ();
+
+  result = CanonicalPath::new_seg (type.get_node_id (), "()");
+}
+
 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 5e382445a148..561948e85b83 100644
--- a/gcc/rust/resolve/rust-ast-resolve-type.h
+++ b/gcc/rust/resolve/rust-ast-resolve-type.h
@@ -248,6 +248,8 @@ public:
 
   void visit (AST::NeverType &type) override;
 
+  void visit (AST::TupleType &type) override;
+
 private:
   ResolveTypeToCanonicalPath ();
 
diff --git a/gcc/testsuite/rust/compile/issue-3036.rs 
b/gcc/testsuite/rust/compile/issue-3036.rs
new file mode 100644
index 000000000000..4418ccc04cb9
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3036.rs
@@ -0,0 +1,14 @@
+#[lang = "sized"]
+trait Sized {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait Default: Sized {
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn default() -> Self;
+}
+
+impl Default for () {
+    fn default() -> () {
+        ()
+    }
+}
diff --git a/gcc/testsuite/rust/compile/nr2/exclude 
b/gcc/testsuite/rust/compile/nr2/exclude
index bfb51fd7fee9..50781e56b85e 100644
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -252,3 +252,4 @@ issue-3082.rs
 issue-3139-1.rs
 issue-3139-2.rs
 issue-3139-3.rs
+issue-3036.rs