gccrs: fix segfault in clone_pattern w macro

gcc/rust/expand/rust-macro-expand.cc

@@ -962,12 +962,10 @@ transcribe_expression (Parser<MacroInvocLexer> &parser)
 
   auto attrs = parser.parse_outer_attributes ();
   auto expr = parser.parse_expr (std::move (attrs));
-  if (expr == nullptr)
-    {
-      for (auto error : parser.get_errors ())
-	error.emit ();
-      return AST::Fragment::create_error ();
-    }
+  for (auto error : parser.get_errors ())
+    error.emit ();
+  if (!expr)
+    return AST::Fragment::create_error ();
 
   // FIXME: make this an error for some edititons
   if (parser.peek_current_token ()->get_id () == SEMICOLON)
@@ -997,6 +995,8 @@ transcribe_type (Parser<MacroInvocLexer> &parser)
   auto type = parser.parse_type (true);
   for (auto err : parser.get_errors ())
     err.emit ();
+  if (!type)
+    return AST::Fragment::create_error ();
 
   auto end = lexer.get_offs ();
 
@@ -1018,6 +1018,9 @@ transcribe_pattern (Parser<MacroInvocLexer> &parser)
   for (auto err : parser.get_errors ())
     err.emit ();
 
+  if (!pattern)
+    return AST::Fragment::create_error ();
+
   auto end = lexer.get_offs ();
 
   return AST::Fragment ({std::move (pattern)},

gcc/testsuite/rust/compile/issue-4140-1.rs

@@ -0,0 +1,18 @@
+pub enum TypeCtor {
+    Slice,
+    Array,
+}
+pub struct B<T>(T);
+
+macro_rules! ty_app {
+    ($_a:pat) => {
+        ApplicationTy($ctor) // { dg-error "unexpected token '$' in typle struct items" "4140" { target *-*-* } . }
+        // { dg-error "failed to parse typle struct items" "4140" { target *-*-*} .-1 }
+    };
+}
+
+pub fn foo(ty: ApplicationTy) { // { dg-error "could not resolve type path 'ApplicationTy'" "4140" { target *-*-* } .-1 }
+    match ty {
+        ty_app!(bean::Array) => {}
+    }
+}

gcc/testsuite/rust/compile/issue-4140-2.rs

@@ -0,0 +1,11 @@
+macro_rules! ty_app {
+    ($_a:pat) => {
+        ($ctor) // { dg-error "unrecognised token '$' in grouped or tuple pattern after first pattern" "4140" { target *-*-* } . }
+    };
+}
+
+pub fn foo() {
+    match ty { // { dg-error "Cannot find path 'ty' in this scope" "4140" { target *-*-* } .-1 }
+        ty_app!(bean::Array) => {}
+    }
+}