Chore ast tree delegate

gcc/rust/ast/rust-item.h

@@ -3197,19 +3197,18 @@ class TraitImpl : public Impl
       trait_path (std::move (trait_path)), impl_items (std::move (impl_items))
   {}
 
-  // Helper constructor with a typepath
+  // Delegating constructor for TypePath
   TraitImpl (TypePath trait_path, bool is_unsafe, bool has_exclam,
 	     std::vector<std::unique_ptr<AssociatedItem>> impl_items,
 	     std::vector<std::unique_ptr<GenericParam>> generic_params,
 	     std::unique_ptr<Type> trait_type, WhereClause where_clause,
 	     Visibility vis, std::vector<Attribute> inner_attrs,
 	     std::vector<Attribute> outer_attrs, location_t locus)
-    : Impl (std::move (generic_params), std::move (trait_type),
-	    std::move (where_clause), std::move (vis), std::move (inner_attrs),
-	    std::move (outer_attrs), locus),
-      has_unsafe (is_unsafe), has_exclam (has_exclam),
-      trait_path (std::unique_ptr<TypePath> (new TypePath (trait_path))),
-      impl_items (std::move (impl_items))
+    : TraitImpl (std::unique_ptr<Path> (new TypePath (trait_path)), is_unsafe,
+		 has_exclam, std::move (impl_items), std::move (generic_params),
+		 std::move (trait_type), std::move (where_clause),
+		 std::move (vis), std::move (inner_attrs),
+		 std::move (outer_attrs), locus)
   {}
 
   // Copy constructor with vector clone

gcc/rust/parse/rust-parse-impl.h

@@ -12023,6 +12023,11 @@ Parser<ManagedTokenSource>::parse_expr (int right_binding_power,
   if (restrictions.expr_can_be_null)
     {
       TokenId id = current_token->get_id ();
+      if (restrictions.stop_on_token && (id == MATCH_ARROW || id == COMMA))
+        {
+          rust_debug ("Stopping Parsing at special token");
+          return nullptr;
+        }
       if (id == SEMICOLON || id == RIGHT_PAREN || id == RIGHT_CURLY
 	  || id == RIGHT_SQUARE || id == COMMA || id == LEFT_CURLY)
 	return nullptr;
@@ -12078,6 +12083,12 @@ Parser<ManagedTokenSource>::left_denotations (std::unique_ptr<AST::Expr> expr,
   while (right_binding_power < left_binding_power (current_token))
     {
       lexer.skip_token ();
+      if (restrictions.stop_on_token
+            && (current_token->get_id() == MATCH_ARROW || current_token->get_id() == COMMA))
+        {
+            rust_debug ("Stopping parsing at restricted token in left_denotations");
+            return expr;
+        }
 
       // FIXME attributes should generally be applied to the null denotation.
       expr = left_denotation (current_token, std::move (expr),
@@ -12115,6 +12126,12 @@ Parser<ManagedTokenSource>::null_denotation (const_TokenPtr tok,
 {
   /* note: tok is previous character in input stream, not current one, as
    * parse_expr skips it before passing it in */
+
+  if (restrictions.stop_on_token && (tok->get_id() == MATCH_ARROW || tok->get_id() == COMMA))
+    {
+        rust_debug("Stopping parsing at restricted token in null_denotation");
+        return nullptr;
+    }
 
   /* as a Pratt parser (which works by decomposing expressions into a null
    * denotation and then a left denotation), null denotations handle primaries

gcc/rust/parse/rust-parse.h

@@ -89,6 +89,7 @@ struct ParseRestrictions
   bool entered_from_unary = false;
   bool expr_can_be_null = false;
   bool expr_can_be_stmt = false;
+  bool stop_on_token = false; // This is for stopping parsing at a specific token
   bool consume_semi = true;
   /* Macro invocations that are statements can expand without a semicolon after
    * the final statement, if it's an expression statement. */