[COMMITTED 137/143] gccrs: Emit error when tuple-indexing on non-tuples

[arthur . cohen]

From: Ryo Yoshida <low.ryosh...@gmail.com>

Fixes Rust-GCC#3927

gcc/rust/ChangeLog:

        * typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit): check
        and properly emit an error when the tuple index is on a 
non-tuple-struct.

gcc/testsuite/ChangeLog:

        * rust/compile/tuple_index_on_non_tuple.rs: New test.

Signed-off-by: Ryo Yoshida <low.ryosh...@gmail.com>
---
 gcc/rust/typecheck/rust-hir-type-check-expr.cc    |  8 +++++++-
 .../rust/compile/tuple_index_on_non_tuple.rs      | 15 +++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/rust/compile/tuple_index_on_non_tuple.rs

diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.cc 
b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
index 71dcaa316ab..7885dfcf746 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
@@ -126,7 +126,13 @@ TypeCheckExpr::visit (HIR::TupleIndexExpr &expr)
     }
 
   TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (resolved);
-  rust_assert (!adt->is_enum ());
+  if (!adt->is_tuple_struct ())
+    {
+      rust_error_at (expr.get_locus (),
+                    "expected tuple or tuple struct, found %qs",
+                    adt->get_name ().c_str ());
+      return;
+    }
   rust_assert (adt->number_of_variants () == 1);
 
   TyTy::VariantDef *variant = adt->get_variants ().at (0);
diff --git a/gcc/testsuite/rust/compile/tuple_index_on_non_tuple.rs 
b/gcc/testsuite/rust/compile/tuple_index_on_non_tuple.rs
new file mode 100644
index 00000000000..f94b8c3d7ee
--- /dev/null
+++ b/gcc/testsuite/rust/compile/tuple_index_on_non_tuple.rs
@@ -0,0 +1,15 @@
+enum E {
+    V(usize),
+}
+
+struct S {
+    field: i32,
+}
+
+fn main() {
+    let e = E::V(0);
+    let _ = e.0; // { dg-error "expected tuple or tuple struct, found 'E'" }
+
+    let s = S { field: 0 };
+    let _ = s.0; // { dg-error "expected tuple or tuple struct, found 'S'" }
+}
-- 
2.50.1