Fix crash for deferred methods introduced by #2193 (self-type). (#2375)

Fixes #2372.

mypy/checker.py

@@ -65,6 +65,7 @@
     [
         ('node', FuncItem),
         ('context_type_name', Optional[str]),  # Name of the surrounding class (for error messages)
+        ('class_type', Optional[Type]),  # And its type (from class_context)
     ])
 
 
@@ -202,13 +203,20 @@ def check_second_pass(self) -> bool:
         todo = self.deferred_nodes
         self.deferred_nodes = []
         done = set()  # type: Set[FuncItem]
-        for node, type_name in todo:
+        for node, type_name, class_type in todo:
             if node in done:
                 continue
+            # This is useful for debugging:
+            # print("XXX in pass %d, class %s, function %s" %
+            #       (self.pass_num, type_name, node.fullname() or node.name()))
             done.add(node)
             if type_name:
                 self.errors.push_type(type_name)
+            if class_type:
+                self.class_context.append(class_type)
             self.accept(node)
+            if class_type:
+                self.class_context.pop()
             if type_name:
                 self.errors.pop_type()
         return True
@@ -221,7 +229,11 @@ def handle_cannot_determine_type(self, name: str, context: Context) -> None:
                 type_name = self.errors.type_name[-1]
             else:
                 type_name = None
-            self.deferred_nodes.append(DeferredNode(node, type_name))
+            if self.class_context:
+                class_context_top = self.class_context[-1]
+            else:
+                class_context_top = None
+            self.deferred_nodes.append(DeferredNode(node, type_name, class_context_top))
             # Set a marker so that we won't infer additional types in this
             # function. Any inferred types could be bogus, because there's at
             # least one type that we don't know.

test-data/unit/check-modules.test

@@ -1296,6 +1296,14 @@ def deco(f: Callable[[T], int]) -> Callable[[T], int]:
 main:1: note: In module imported here:
 tmp/a.py:6: error: Revealed type is 'def (builtins.str*) -> builtins.int'
 
+[case testDeferredClassContext]
+class A:
+    def f(self) -> str: return 'foo'
+class B(A):
+    def f(self) -> str: return self.x
+    def initialize(self): self.x = 'bar'
+[out]
+
 
 -- Scripts and __main__