gccrs: Fix ICE on raw reference

This patch adds support for raw references which enforce the pointer
type away from a reference type.

Fixes Rust-GCC#3667

gcc/rust/ChangeLog:

	* backend/rust-compile-base.cc (HIRCompileBase::address_expression): allow optional type
	* backend/rust-compile-base.h: update prototype
	* backend/rust-compile-expr.cc (CompileExpr::visit): update borrow expr
	* backend/rust-compile-extern.h: remove unused debug
	* backend/rust-compile-resolve-path.cc (HIRCompileBase::query_compile): update usage
	* hir/rust-ast-lower-expr.cc (ASTLoweringExpr::visit): lower raw ref
	* hir/tree/rust-hir-expr.cc (BorrowExpr::BorrowExpr): add flag for raw ref
	* hir/tree/rust-hir-expr.h (class BorrowExpr): add new raw ref field
	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit): add handle for raw ref

gcc/testsuite/ChangeLog:

	* rust/compile/issue-3667.rs: New test.

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

1 files changed, 24 insertions, 0 deletions

diff --git a/gcc/testsuite/rust/compile/issue-3667.rs b/gcc/testsuite/rust/compile/issue-3667.rs
new file mode 100644
index 0000000..e72069c
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3667.rs
@@ -0,0 +1,24 @@
+// { dg-options "-w" }
+#![feature(raw_ref_op)]
+
+const pq1: () = {
+    let mut x = 2;
+    &raw mut x;
+}; //~ mutable reference
+
+static B: () = {
+    let mut x = 2;
+    &raw mut x;
+}; //~ mutable reference
+
+static mut C: () = {
+    let mut x = 2;
+    &raw mut x;
+}; //~ mutable reference
+
+const fn foo() {
+    let mut x = 0;
+    let y = &raw mut x; //~ mutable reference
+}
+
+fn main() {}