Infer type for targets initialized through TypeVar(...) (PY-28227)

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) {

python/testData/types/TypeVarTargetStub/a.py

@@ -0,0 +1,3 @@
+from typing import TypeVar
+
+T = TypeVar('T')

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());