From: Philip Herron <herron.philip@googlemail.com>
Date: Wed, 17 Sep 2025 13:24:38 +0000 (+0100)
Subject: gccrs: Fix ICE for invalid const capacity expression handling
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=68a0e459c05aa080d8b97f5887d8f321d9749f7b;p=thirdparty%2Fgcc.git

gccrs: Fix ICE for invalid const capacity expression handling

When we have an invalid capacity expression we can't try to then also
const fold it as GCC will assert on invalid conversions.

Fixes Rust-GCC#4168

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-type.cc (TypeCheckType::visit): check for invalid capacity

gcc/testsuite/ChangeLog:

	* rust/compile/issue-4168.rs: New test.

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

diff --git a/gcc/rust/typecheck/rust-hir-type-check-type.cc b/gcc/rust/typecheck/rust-hir-type-check-type.cc
index dfefae8bef3..833ad92db59 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-type.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-type.cc
@@ -720,19 +720,32 @@ TypeCheckType::visit (HIR::ArrayType &type)
   else
     {
       HirId size_id = type.get_size_expr ().get_mappings ().get_hirid ();
-      unify_site (size_id, TyTy::TyWithLocation (expected_ty),
-		  TyTy::TyWithLocation (capacity_type,
-					type.get_size_expr ().get_locus ()),
-		  type.get_size_expr ().get_locus ());
+      TyTy::BaseType *result
+	= unify_site (size_id, TyTy::TyWithLocation (expected_ty),
+		      TyTy::TyWithLocation (capacity_type,
+					    type.get_size_expr ().get_locus ()),
+		      type.get_size_expr ().get_locus ());
 
-      auto ctx = Compile::Context::get ();
-      tree capacity_expr = Compile::HIRCompileBase::query_compile_const_expr (
-	ctx, capacity_type, type.get_size_expr ());
-
-      const_type = new TyTy::ConstType (TyTy::ConstType::ConstKind::Value, "",
-					expected_ty, capacity_expr, {},
-					type.get_size_expr ().get_locus (),
-					size_id, size_id);
+      if (result->is<TyTy::ErrorType> ())
+	{
+	  const_type
+	    = new TyTy::ConstType (TyTy::ConstType::ConstKind::Error, "",
+				   expected_ty, error_mark_node, {},
+				   type.get_size_expr ().get_locus (), size_id,
+				   size_id);
+	}
+      else
+	{
+	  auto ctx = Compile::Context::get ();
+	  tree capacity_expr
+	    = Compile::HIRCompileBase::query_compile_const_expr (
+	      ctx, capacity_type, type.get_size_expr ());
+
+	  const_type = new TyTy::ConstType (TyTy::ConstType::ConstKind::Value,
+					    "", expected_ty, capacity_expr, {},
+					    type.get_size_expr ().get_locus (),
+					    size_id, size_id);
+	}
     }
 
   translated
diff --git a/gcc/testsuite/rust/compile/issue-4168.rs b/gcc/testsuite/rust/compile/issue-4168.rs
new file mode 100644
index 00000000000..abb1190ebc3
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-4168.rs
@@ -0,0 +1,7 @@
+const fn add(x: usize, y: usize) -> i32 {
+    add + y
+    // { dg-error "cannot apply operator .+. to types fn .x usize,y usize,. -> i32 and usize" "" { target *-*-* } .-1 }
+}
+const ARR: [i32; add(1, 2)] = [5, 6, 1];
+// { dg-error "mismatched types, expected .usize. but got .i32. .E0308." "" { target *-*-* } .-1 }
+// { dg-error "mismatched types" "" { target *-*-* } .-2 }