Back-port of rev 61240 for issue #2238, fixing: Some syntax errors in *args

and **kwargs expressions could give bogus error messages.

Lib/test/test_grammar.py

@@ -260,6 +260,10 @@ d31v(1)
 def d32v((x,)): pass
 d32v((1,))
 
+# Check ast errors in *args and *kwargs
+check_syntax("f(*g(1=2))")
+check_syntax("f(**g(1=2))")
+
 ### lambdef: 'lambda' [varargslist] ':' test
 print 'lambdef'
 l1 = lambda : 0

Misc/NEWS

@@ -14,6 +14,9 @@ Core and builtins
 - Issue #2321: use pymalloc for unicode object string data to reduce
   memory usage in some circumstances.
 
+- Issue #2238: Some syntax errors in *args and **kwargs expressions could give
+  bogus error messages.
+
 Library
 -------
 

Python/ast.c

@@ -1878,10 +1878,14 @@ ast_for_call(struct compiling *c, const node *n, expr_ty func)
 	}
 	else if (TYPE(ch) == STAR) {
 	    vararg = ast_for_expr(c, CHILD(n, i+1));
+	    if (!vararg)
+	        return NULL;
 	    i++;
 	}
 	else if (TYPE(ch) == DOUBLESTAR) {
 	    kwarg = ast_for_expr(c, CHILD(n, i+1));
+	    if (!kwarg)
+	        return NULL;
 	    i++;
 	}
     }