1 files changed, 8 insertions, 1 deletions
diff --git a/Grammar/python.gram b/Grammar/python.gram
index de435537095..d1af7704e9b 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -184,7 +184,9 @@ return_stmt[stmt_ty]:
     | 'return' a=[star_expressions] { _PyAST_Return(a, EXTRA) }
 
 raise_stmt[stmt_ty]:
-    | 'raise' a=expression b=['from' z=expression { z }] { _PyAST_Raise(a, b, EXTRA) }
+    | 'raise' a=expression 'from' b=expression { _PyAST_Raise(a, b, EXTRA) }
+    | invalid_raise_stmt
+    | 'raise' a=expression { _PyAST_Raise(a, NULL, EXTRA) }
     | 'raise' { _PyAST_Raise(NULL, NULL, EXTRA) }
 
 pass_stmt[stmt_ty]:
@@ -1287,6 +1289,11 @@ invalid_ann_assign_target[expr_ty]:
     | list
     | tuple
     | '(' a=invalid_ann_assign_target ')' { a }
+invalid_raise_stmt:
+    | a='raise' b='from' {
+        RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "did you forget an expression between 'raise' and 'from'?") }
+    | 'raise' expression a='from' {
+        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "did you forget an expression after 'from'?") }
 invalid_del_stmt:
     | 'del' a=star_expressions {
         RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) }