From: Philip Herron <herron.philip@googlemail.com>
Date: Sun, 21 Sep 2025 17:56:55 +0000 (+0100)
Subject: gccrs: Fix ICE on copied array expressions
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cca063c47059a6c4475356a9eee5559262c89d21;p=thirdparty%2Fgcc.git

gccrs: Fix ICE on copied array expressions

We need to check for errors on the number of copies expression before
trying to const fold it otherwise it will just fail in the const evaluator.

Fixes Rust-GCC#4165

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit): check for error

gcc/testsuite/ChangeLog:

	* rust/compile/issue-4165.rs: New test.

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

diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.cc b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
index 05749609a20..c7f8192bada 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
@@ -1096,11 +1096,13 @@ TypeCheckExpr::visit (HIR::ArrayExpr &expr)
 	context->insert_type (elems.get_num_copies_expr ().get_mappings (),
 			      expected_ty);
 
-	unify_site (
+	auto result = unify_site (
 	  expr.get_mappings ().get_hirid (), TyTy::TyWithLocation (expected_ty),
 	  TyTy::TyWithLocation (capacity_expr_ty,
 				elems.get_num_copies_expr ().get_locus ()),
 	  expr.get_locus ());
+	if (result->is<TyTy::ErrorType> ())
+	  return;
 
 	capacity_expr = &elems.get_num_copies_expr ();
 	capacity_type = expected_ty;
diff --git a/gcc/testsuite/rust/compile/issue-4165.rs b/gcc/testsuite/rust/compile/issue-4165.rs
new file mode 100644
index 00000000000..bc513da3936
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-4165.rs
@@ -0,0 +1,12 @@
+const N: usize = 2;
+const ARR: [i32; N] = [42; X];
+// { dg-error {cannot find value .X. in this scope \[E0425\]} "" { target *-*-* } .-1 }
+// { dg-error {mismatched types, expected .\[i32; 2]. but got .<tyty::error>. \[E0308\]} "" { target *-*-* } .-2 }
+// { dg-error {mismatched types, expected .usize. but got .bool. \[E0308\]} "" { target *-*-* } .-3 }
+const X: bool = (N[0] == 99) && (ARR[0] == 0);
+// { dg-error {the type .usize. cannot be indexed by .<integer>. \[E0277\]} "" { target *-*-* } .-1 }
+// { dg-error {mismatched types, expected .<tyty::error>. but got .<integer>. \[E0308\]} "" { target *-*-* } .-2 }
+
+fn main() {
+    let _ = X;
+}