From 437b18316016fa1730ee83b17bdd6d6783a492c2 Mon Sep 17 00:00:00 2001
From: Semyon Proshev <Semyon.Proshev@jetbrains.com>
Date: Thu, 12 Apr 2018 17:03:24 +0300
Subject: [PATCH] Infer type for targets initialized through `TypeVar(...)`
 (PY-28227)

---
 .../codeInsight/typing/PyTypingTypeProvider.java   |  8 ++++++++
 python/testData/types/TypeVarTargetStub/a.py       |  3 +++
 .../testSrc/com/jetbrains/python/PyTypeTest.java   | 14 ++++++++++++++
 3 files changed, 25 insertions(+)
 create mode 100644 python/testData/types/TypeVarTargetStub/a.py

diff --git a/python/src/com/jetbrains/python/codeInsight/typing/PyTypingTypeProvider.java b/python/src/com/jetbrains/python/codeInsight/typing/PyTypingTypeProvider.java
index cacc3955f760..2408aa0598f1 100644
--- a/python/src/com/jetbrains/python/codeInsight/typing/PyTypingTypeProvider.java
+++ b/python/src/com/jetbrains/python/codeInsight/typing/PyTypingTypeProvider.java
@@ -491,6 +491,14 @@ public class PyTypingTypeProvider extends PyTypeProviderBase {
         return annotatedType;
       }
 
+      final PyExpression assignedValue = PyTypingAliasStubType.getAssignedValueStubLike(target);
+      if (assignedValue != null) {
+        final PyType type = getGenericTypeFromTypeVar(assignedValue, new Context(context));
+        if (type != null) {
+          return Ref.create(type);
+        }
+      }
+
       final String name = target.getReferencedName();
       final ScopeOwner scopeOwner = ScopeUtil.getScopeOwner(target);
       if (name == null || scopeOwner == null) {
diff --git a/python/testData/types/TypeVarTargetStub/a.py b/python/testData/types/TypeVarTargetStub/a.py
new file mode 100644
index 000000000000..65b5ccfa7d2d
--- /dev/null
+++ b/python/testData/types/TypeVarTargetStub/a.py
@@ -0,0 +1,3 @@
+from typing import TypeVar
+
+T = TypeVar('T')
\ No newline at end of file
diff --git a/python/testSrc/com/jetbrains/python/PyTypeTest.java b/python/testSrc/com/jetbrains/python/PyTypeTest.java
index 36775cc5492b..17500d3eafea 100644
--- a/python/testSrc/com/jetbrains/python/PyTypeTest.java
+++ b/python/testSrc/com/jetbrains/python/PyTypeTest.java
@@ -3230,6 +3230,20 @@ public class PyTypeTest extends PyTestCase {
     doTest("float", "expr = round(True, 1)");
   }
 
+  // PY-28227
+  public void testTypeVarTargetAST() {
+    doTest("T",
+           "from typing import TypeVar\n" +
+           "expr = TypeVar('T')");
+  }
+
+  // PY-28227
+  public void testTypeVarTargetStub() {
+    doMultiFileTest("T",
+                    "from a import T\n" +
+                    "expr = T");
+  }
+
   private static List<TypeEvalContext> getTypeEvalContexts(@NotNull PyExpression element) {
     return ImmutableList.of(TypeEvalContext.codeAnalysis(element.getProject(), element.getContainingFile()).withTracing(),
                             TypeEvalContext.userInitiated(element.getProject(), element.getContainingFile()).withTracing());