PY-31424 Adjust the signature to TypeVar to accept type references

One can pass string literals containing such references both to "*constraints"
and "bound" parameters.

python/src/com/jetbrains/python/codeInsight/typing/PyTypingTypeProvider.java

@@ -312,8 +312,9 @@ public class PyTypingTypeProvider extends PyTypeProviderBase {
       final PyElementGenerator generator = PyElementGenerator.getInstance(referenceExpression.getProject());
 
       parameters.add(PyCallableParameterImpl.nonPsi("name", builtinCache.getStringType(languageLevel)));
-      parameters.add(PyCallableParameterImpl.positionalNonPsi("constraints", builtinCache.getTypeType()));
-      parameters.add(PyCallableParameterImpl.nonPsi("bound", builtinCache.getTypeType(), generator.createEllipsis()));
+      final PyType typeOrForwardReference = PyUnionType.union(builtinCache.getTypeType(), builtinCache.getStrType());
+      parameters.add(PyCallableParameterImpl.positionalNonPsi("constraints", typeOrForwardReference));
+      parameters.add(PyCallableParameterImpl.nonPsi("bound", typeOrForwardReference, generator.createEllipsis()));
 
       final PyClassType boolType = builtinCache.getBoolType();
       final PyExpression falseValue = generator.createExpressionFromText(languageLevel, "False");

python/testData/inspections/PyTypeCheckerInspection/InitializingTypeVar.py

@@ -1,4 +1,7 @@
 from typing import TypeVar
 
 TypeVar("T", int, str, bound=int, covariant=True, contravariant=True)
-TypeVar("T", <warning descr="Expected type 'type', got 'int' instead">0</warning>, <warning descr="Expected type 'type', got 'int' instead">1</warning>, <warning descr="Expected type 'type', got 'int' instead">bound=2</warning>, <warning descr="Expected type 'bool', got 'int' instead">covariant=3</warning>, <warning descr="Expected type 'bool', got 'int' instead">contravariant=4</warning>)
+TypeVar("T", int, str, bound='int', covariant=True, contravariant=True)
+TypeVar("T", int, 'str', bound=int, covariant=True, contravariant=True)
+TypeVar("T", 'int', 'str', bound=int, covariant=True, contravariant=True)
+TypeVar("T", <warning descr="Expected type 'Union[type, str]', got 'int' instead">0</warning>, <warning descr="Expected type 'Union[type, str]', got 'int' instead">1</warning>, <warning descr="Expected type 'Union[type, str]', got 'int' instead">bound=2</warning>, <warning descr="Expected type 'bool', got 'int' instead">covariant=3</warning>, <warning descr="Expected type 'bool', got 'int' instead">contravariant=4</warning>)

python/testSrc/com/jetbrains/python/PyParameterInfoTest.java

@@ -846,14 +846,15 @@ public class PyParameterInfoTest extends LightMarkedTestCase {
     );
   }
 
-  // PY-28127
+  // PY-28127 PY-31424
   public void testInitializingTypeVar() {
     runWithLanguageLevel(
       LanguageLevel.PYTHON34,
       () -> {
         final int offset = loadTest(1).get("<arg1>").getTextOffset();
 
-        feignCtrlP(offset).check("name: str, *constraints: type, bound: type=..., covariant: bool=False, contravariant: bool=False",
+        feignCtrlP(offset).check("name: str, *constraints: Union[type, str], bound: Union[type, str]=..., " +
+                                 "covariant: bool=False, contravariant: bool=False",
                                  new String[]{"name: str, "},
                                  ArrayUtil.EMPTY_STRING_ARRAY);
       }

python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java

@@ -81,7 +81,7 @@ public class Py3TypeCheckerInspectionTest extends PyInspectionTestCase {
   public void testStrFormatPy3() {
     doTest();
   }
-  
+
   // PY-18762
   public void testHomogeneousTuples() {
     doTest();
@@ -341,7 +341,7 @@ public class Py3TypeCheckerInspectionTest extends PyInspectionTestCase {
     runWithLanguageLevel(LanguageLevel.PYTHON37, () -> super.doMultiFileTest());
   }
 
-  // PY-28127
+  // PY-28127 PY-31424
   public void testInitializingTypeVar() {
     doTest();
   }