[COMMITTED 129/220] gccrs: ast: Check before visiting a while-let's label

[arthur . cohen]

From: Arthur Cohen <arthur.co...@embecosm.com>

gcc/rust/ChangeLog:

        * ast/rust-ast-visitor.cc (DefaultASTVisitor::visit): Check that the 
WhileLet has a label
        before visiting it.

gcc/testsuite/ChangeLog:

        * rust/compile/while_let_without_label.rs: New test.
---
 gcc/rust/ast/rust-ast-visitor.cc                      |  5 ++++-
 gcc/testsuite/rust/compile/while_let_without_label.rs | 11 +++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/rust/compile/while_let_without_label.rs

diff --git a/gcc/rust/ast/rust-ast-visitor.cc b/gcc/rust/ast/rust-ast-visitor.cc
index fd45fb1060d..ca7b3e495d0 100644
--- a/gcc/rust/ast/rust-ast-visitor.cc
+++ b/gcc/rust/ast/rust-ast-visitor.cc
@@ -601,7 +601,10 @@ DefaultASTVisitor::visit (AST::WhileLetLoopExpr &expr)
   visit_outer_attrs (expr);
   for (auto &pattern : expr.get_patterns ())
     visit (pattern);
-  visit (expr.get_loop_label ());
+
+  if (expr.has_loop_label ())
+    visit (expr.get_loop_label ());
+
   visit (expr.get_scrutinee_expr ());
   visit (expr.get_loop_block ());
 }
diff --git a/gcc/testsuite/rust/compile/while_let_without_label.rs 
b/gcc/testsuite/rust/compile/while_let_without_label.rs
new file mode 100644
index 00000000000..e04e4b59d1d
--- /dev/null
+++ b/gcc/testsuite/rust/compile/while_let_without_label.rs
@@ -0,0 +1,11 @@
+// { dg-additional-options "-frust-compile-until=lowering" }
+
+enum Foo {
+    A(i32),
+}
+
+fn main() {
+    let b = Foo::A(15);
+
+    while let Foo::A(x) = b {}
+}
-- 
2.49.0