Prevent crash on retrieving TypeVar from class (python#2544)

* Add test for accessing TypeVar class members

* Add trailing newline

* TypeVar class members should have the type TypeVarType

Author: TRManderson

mypy/checkmember.py

@@ -7,7 +7,7 @@
     Overloaded, TypeVarType, UnionType, PartialType,
     DeletedType, NoneTyp, TypeType, function_type
 )
-from mypy.nodes import TypeInfo, FuncBase, Var, FuncDef, SymbolNode, Context, MypyFile
+from mypy.nodes import TypeInfo, FuncBase, Var, FuncDef, SymbolNode, Context, MypyFile, TypeVarExpr
 from mypy.nodes import ARG_POS, ARG_STAR, ARG_STAR2
 from mypy.nodes import Decorator, OverloadedFuncDef
 from mypy.messages import MessageBuilder
@@ -379,6 +379,9 @@ def analyze_class_attribute_access(itype: Instance,
         not_ready_callback(name, context)
         return AnyType()
 
+    if isinstance(node.node, TypeVarExpr):
+        return TypeVarType(node.tvar_def, node.tvar_def.line, node.tvar_def.column)
+
     if isinstance(node.node, TypeInfo):
         return type_object_type(node.node, builtin_type)
 

test-data/unit/check-typevar-values.test

@@ -489,3 +489,11 @@ def outer(x: T) -> T:
         return inner1('a') # E: Argument 1 to "inner1" has incompatible type "str"; expected "int"
     return inner1(x)
 [out]
+
+[case testClassMemberTypeVarInFunctionBody]
+from typing import TypeVar
+class C:
+    T = TypeVar('T', int)
+    def f(self, x: T) -> T:
+        A = C.T
+        return x