Added special-case handling for EnumMeta.

server/src/analyzer/typeUtils.ts

@@ -449,6 +449,13 @@ export function canAssignType(destType: Type, srcType: Type, diag: DiagnosticAdd
                 if (isAnyOrUnknown(metaclass)) {
                     return true;
                 } else if (metaclass.category === TypeCategory.Class) {
+                    // Handle EnumMeta, which requires special-case handling because
+                    // of the way it's defined in enum.pyi. The type var _T must be
+                    // manually set to the corresponding enum object type.
+                    if (typeVarMap && ClassType.isBuiltIn(metaclass, 'EnumMeta')) {
+                        typeVarMap.set('_T', ObjectType.create(srcType));
+                    }
+
                     return _canAssignClass(destClassType, metaclass,
                             diag, typeVarMap, flags, recursionCount + 1, false);
                 }

server/src/tests/samples/enums1.py

@@ -1,6 +1,7 @@
 # This sample tests the type checker's handling of Enum.
 
 from enum import Enum, IntEnum
+from typing import List
 
 
 TestEnum1 = Enum("TestEnum1", "A B C D")
@@ -32,3 +33,16 @@ b = TestEnum3.B
 # This should generate an error because "Z" isn't
 # a valid member.
 z = TestEnum3.Z
+
+
+# Test that enum classes are iterable.
+def requires_enum3_list(a: List[TestEnum3]):
+    return
+
+list1 = list(TestEnum3)
+requires_enum3_list(list1)
+
+list2 = [i for i in TestEnum3]
+requires_enum3_list(list2)
+
+num_items_in_enum3 = len(TestEnum3)