[COMMITTED 116/143] gccrs: Fix ICE where we expect a num enum variant

[arthur . cohen]

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

This changes the assertion into a valid error diagnostic.

Fixes Rust-GCC#3538

gcc/rust/ChangeLog:

        * backend/rust-compile-resolve-path.cc: add error diag

gcc/testsuite/ChangeLog:

        * rust/compile/issue-3538.rs: New test.

Signed-off-by: Philip Herron <herron.phi...@googlemail.com>
---
 gcc/rust/backend/rust-compile-resolve-path.cc | 7 +++++--
 gcc/testsuite/rust/compile/issue-3538.rs      | 9 +++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/rust/compile/issue-3538.rs

diff --git a/gcc/rust/backend/rust-compile-resolve-path.cc 
b/gcc/rust/backend/rust-compile-resolve-path.cc
index f3b9dc28db2..c33d0b072d0 100644
--- a/gcc/rust/backend/rust-compile-resolve-path.cc
+++ b/gcc/rust/backend/rust-compile-resolve-path.cc
@@ -97,8 +97,11 @@ ResolvePathRef::attempt_constructor_expression_lookup (
 
   // this can only be for discriminant variants the others are built up
   // using call-expr or struct-init
-  rust_assert (variant->get_variant_type ()
-              == TyTy::VariantDef::VariantType::NUM);
+  if (variant->get_variant_type () != TyTy::VariantDef::VariantType::NUM)
+    {
+      rust_error_at (expr_locus, "variant expected constructor call");
+      return error_mark_node;
+    }
 
   // we need the actual gcc type
   tree compiled_adt_type = TyTyResolveCompile::compile (ctx, adt);
diff --git a/gcc/testsuite/rust/compile/issue-3538.rs 
b/gcc/testsuite/rust/compile/issue-3538.rs
new file mode 100644
index 00000000000..72694571f88
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3538.rs
@@ -0,0 +1,9 @@
+enum A {
+    Value(()),
+}
+
+fn main() {
+    let a = A::Value(());
+    a == A::Value;
+    // { dg-error "variant expected constructor call" "" { target *-*-* } .-1 }
+}
-- 
2.50.1