Fixed bug that causes a false positive overlapping overload error whe…

…n the overload accepts a `Callable[..., T]` form. This addresses #9514. (#9516)

packages/pyright-internal/src/analyzer/typeEvaluator.ts

@@ -26416,6 +26416,16 @@ export function createTypeEvaluator(
             }
         }
 
+        // If we're checking for full overlapping overloads and the source is
+        // a gradual form, the dest must also be a gradual form.
+        if (
+            (flags & AssignTypeFlags.OverloadOverlap) !== 0 &&
+            FunctionType.isGradualCallableForm(srcType) &&
+            !FunctionType.isGradualCallableForm(destType)
+        ) {
+            canAssign = false;
+        }
+
         // If the source and the dest are using the same ParamSpec, any additional
         // concatenated parameters must match.
         if (targetIncludesParamSpec && srcParamSpec?.priv.nameWithScope === destParamSpec?.priv.nameWithScope) {

packages/pyright-internal/src/tests/samples/overloadOverlap1.py

@@ -446,3 +446,34 @@ def func28(a: int, /, b: None = ...) -> None: ...
 @overload
 def func28(a: int, /) -> bool: ...
 def func28(a: int, /, b: bool | None = None) -> bool | None: ...
+
+
+class CBProto29(Protocol):
+    def __call__(self, *args: Any) -> Any: ...
+
+
+@overload
+def func29(func: CBProto29) -> None: ...
+
+
+@overload
+def func29(func: Callable[..., Any]) -> None: ...
+
+
+def func29(func: Any) -> None: ...
+
+
+class CBProto30(Protocol):
+    def __call__(self, *args: Any, **kwargs: Any) -> Any: ...
+
+
+@overload
+def func30(func: CBProto30) -> None: ...
+
+
+@overload
+# This should generate an error because this overload will never be used.
+def func30(func: Callable[..., Any]) -> None: ...
+
+
+def func30(func: Any) -> None: ...

packages/pyright-internal/src/tests/typeEvaluator6.test.ts

@@ -113,7 +113,7 @@ test('OverloadOverlap1', () => {
 
     configOptions.diagnosticRuleSet.reportOverlappingOverload = 'error';
     analysisResults = TestUtils.typeAnalyzeSampleFiles(['overloadOverlap1.py'], configOptions);
-    TestUtils.validateResults(analysisResults, 14);
+    TestUtils.validateResults(analysisResults, 15);
 });
 
 test('TypeGuard1', () => {