Match protocol usage against definition to get correct substitutions (PY-13750)

python/src/com/jetbrains/python/psi/types/PyTypeChecker.java

@@ -296,6 +296,16 @@ public class PyTypeChecker {
         }
       }
 
+      final PyType originalProtocolGenericType = StreamEx
+        .of(Extensions.getExtensions(PyTypeProvider.EP_NAME))
+        .map(provider -> provider.getGenericType(superClass, context.context))
+        .findFirst(Objects::nonNull)
+        .orElse(null);
+
+      // actual was matched against protocol definition above
+      // and here protocol usage is matched against its definition to update substitutions
+      match(expected, originalProtocolGenericType, context);
+
       return Optional.of(true);
     }
 

python/testData/inspections/PyTypeCheckerInspection/BuiltinsPy3.py

@@ -13,4 +13,4 @@ def test_numerics():
     divmod(False, False)
     divmod(<warning descr="Expected type '_N', got 'bytes' instead">b'foo'</warning>, <warning descr="Expected type '_N', got 'str' instead">'bar'</warning>)
     pow(False, True)
-    round<warning descr="Unexpected type(s):(bool, str)Possible types:(SupportsRound, int)(float, int)">(False, 'foo')</warning>
+    round<warning descr="Unexpected type(s):(bool, str)Possible types:(SupportsRound[int], int)(float, int)">(False, 'foo')</warning>

python/testSrc/com/jetbrains/python/Py3TypeTest.java

@@ -974,6 +974,18 @@ public class Py3TypeTest extends PyTestCase {
     );
   }
 
+  // PY-13750
+  public void testBuiltinRound() {
+    doTest("int", "expr = round(1)");
+    doTest("Union[float, int]", "expr = round(1, 1)");
+
+    doTest("int", "expr = round(1.1)");
+    doTest("Union[float, int]", "expr = round(1.1, 1)");
+
+    doTest("int", "expr = round(True)");
+    doTest("Union[float, int]", "expr = round(True, 1)");
+  }
+
   private void doTest(final String expectedType, final String text) {
     myFixture.configureByText(PythonFileType.INSTANCE, text);
     final PyExpression expr = myFixture.findElementByText("expr", PyExpression.class);

python/testSrc/com/jetbrains/python/PyTypeTest.java

@@ -3218,6 +3218,18 @@ public class PyTypeTest extends PyTestCase {
     );
   }
 
+  // PY-13750
+  public void testBuiltinRound() {
+    doTest("float", "expr = round(1)");
+    doTest("float", "expr = round(1, 1)");
+
+    doTest("float", "expr = round(1.1)");
+    doTest("float", "expr = round(1.1, 1)");
+
+    doTest("float", "expr = round(True)");
+    doTest("float", "expr = round(True, 1)");
+  }
+
   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());