Make parsing of ignore annotations more robust

Author: JukkaL

mypy/parse.py

@@ -1564,9 +1564,11 @@ def expect_type(self, typ: type) -> Token:
     def expect_colon_and_break(self) -> Tuple[Token, Token]:
         return self.expect_type(Colon), self.expect_type(Break)
 
+    type_ignore_exp = re.compile(r'[ \t]*#[ \t]*type:[ \t]*ignore\b')
+
     def expect_break(self) -> Token:
         token = self.expect_type(Break)
-        if '# type: ignore' in token.pre:
+        if re.match(self.type_ignore_exp, token.pre):
             self.ignored_lines.add(token.line)
         return token
 

mypy/test/data/parse.test

@@ -3261,3 +3261,34 @@ MypyFile:1(
   ExpressionStmt:3(
     NameExpr(z))
   IgnoredLines(2, 3))
+
+[case testCommentedOutIgnoreAnnotation]
+y ## type: ignore
+[out]
+MypyFile:1(
+  ExpressionStmt:1(
+    NameExpr(y)))
+
+[case testInvalidIgnoreAnnotations]
+y # type: ignored
+y # type: IGNORE
+y # type : ignore
+[out]
+MypyFile:1(
+  ExpressionStmt:1(
+    NameExpr(y))
+  ExpressionStmt:2(
+    NameExpr(y))
+  ExpressionStmt:3(
+    NameExpr(y)))
+
+[case testSpaceInIgnoreAnnotations]
+y #  type:  ignore    # foo
+y #type:ignore
+[out]
+MypyFile:1(
+  ExpressionStmt:1(
+    NameExpr(y))
+  ExpressionStmt:2(
+    NameExpr(y))
+  IgnoredLines(1, 2))