[gcc/devel/rust/master] gccrs: Fix ICE on invalid match arms

[Thomas Schwinge via Gcc-cvs]

https://gcc.gnu.org/g:002c349b6d0f8c12d26beaff178785524f155583

commit 002c349b6d0f8c12d26beaff178785524f155583
Author: Philip Herron <herron.phi...@googlemail.com>
Date:   Thu Apr 3 15:37:40 2025 +0100

    gccrs: Fix ICE on invalid match arms
    
    We hit assertions on empty enum or unknown variant, this catches the error
    and emits a new diagnostic.
    
    Fixes Rust-GCC#3656
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-hir-type-check-pattern.cc 
(TypeCheckPattern::visit): emit error
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/issue-3656.rs: New test.
    
    Signed-off-by: Philip Herron <herron.phi...@googlemail.com>

Diff:
---
 gcc/rust/typecheck/rust-hir-type-check-pattern.cc | 21 +++++++++++++++++++--
 gcc/testsuite/rust/compile/issue-3656.rs          | 10 ++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc 
b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
index eb3c4162bf46..1543d6212866 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
@@ -277,7 +277,15 @@ TypeCheckPattern::visit (HIR::StructPattern &pattern)
 
   infered = pattern_ty;
   TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (infered);
-  rust_assert (adt->number_of_variants () > 0);
+  if (adt->number_of_variants () == 0)
+    {
+      HIR::PathInExpression &path = pattern.get_path ();
+      const AST::SimplePath &sp = path.as_simple_path ();
+      rust_error_at (pattern.get_locus (), ErrorCode::E0574,
+                    "expected struct, variant or union type, found enum %qs",
+                    sp.as_string ().c_str ());
+      return;
+    }
 
   TyTy::VariantDef *variant = adt->get_variants ().at (0);
   if (adt->is_enum ())
@@ -285,7 +293,16 @@ TypeCheckPattern::visit (HIR::StructPattern &pattern)
       HirId variant_id = UNKNOWN_HIRID;
       bool ok = context->lookup_variant_definition (
        pattern.get_path ().get_mappings ().get_hirid (), &variant_id);
-      rust_assert (ok);
+      if (!ok)
+       {
+         HIR::PathInExpression &path = pattern.get_path ();
+         const AST::SimplePath &sp = path.as_simple_path ();
+         rust_error_at (
+           pattern.get_locus (), ErrorCode::E0574,
+           "expected struct, variant or union type, found enum %qs",
+           sp.as_string ().c_str ());
+         return;
+       }
 
       ok = adt->lookup_variant_by_id (variant_id, &variant);
       rust_assert (ok);
diff --git a/gcc/testsuite/rust/compile/issue-3656.rs 
b/gcc/testsuite/rust/compile/issue-3656.rs
new file mode 100644
index 000000000000..e0bec2fa4a69
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3656.rs
@@ -0,0 +1,10 @@
+enum Foo {
+    Bar(isize),
+}
+
+fn main() {
+    match Foo::Bar(205) {
+        Foo { i } => (),
+        // { dg-error "expected struct, variant or union type, found enum 
.Foo. .E0574." "" { target *-*-* } .-1 }
+    }
+}