From 4cb43d39a33e507e4be9b27bb23c297ecd1c485b Mon Sep 17 00:00:00 2001
From: detachhead <detachhead@users.noreply.github.com>
Date: Mon, 16 Dec 2024 22:01:31 +1000
Subject: [PATCH] fix `reportUnusedParameter` false positive on abstract
 setters

---
 packages/pyright-internal/src/analyzer/properties.ts |  8 ++++++++
 .../pyright-internal/src/analyzer/typeEvaluator.ts   |  1 +
 .../src/analyzer/typeEvaluatorTypes.ts               |  1 +
 packages/pyright-internal/src/analyzer/typeUtils.ts  |  3 ++-
 .../src/tests/samples/reportUnusedParameter.py       | 12 ++++++++++--
 5 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/packages/pyright-internal/src/analyzer/properties.ts b/packages/pyright-internal/src/analyzer/properties.ts
index be6536b636..a55fa483f2 100644
--- a/packages/pyright-internal/src/analyzer/properties.ts
+++ b/packages/pyright-internal/src/analyzer/properties.ts
@@ -121,6 +121,14 @@ export function clonePropertyWithSetter(
     if (!isProperty(prop)) {
         return prop;
     }
+    // this is safe. see comment on isProperty
+    prop = prop as ClassType;
+
+    // if it's an abstract property, mark the parameter as accessed
+    if (prop.priv?.fgetInfo?.methodType && FunctionType.isAbstractMethod(prop.priv.fgetInfo.methodType)) {
+        // first parameter is self, there should only ever be one other parameter.
+        evaluator.markParamAccessed(errorNode.d.params[1]);
+    }
 
     const classType = prop as ClassType;
     const flagsToClone = classType.shared.flags;
diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
index ca4f8bf7ef..7549202eb9 100644
--- a/packages/pyright-internal/src/analyzer/typeEvaluator.ts
+++ b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -28434,6 +28434,7 @@ export function createTypeEvaluator(
         checkForCancellation,
         printControlFlowGraph,
         typesOverlap,
+        markParamAccessed,
     };
 
     const codeFlowEngine = getCodeFlowEngine(evaluatorInterface, speculativeTypeTracker);
diff --git a/packages/pyright-internal/src/analyzer/typeEvaluatorTypes.ts b/packages/pyright-internal/src/analyzer/typeEvaluatorTypes.ts
index fc3a7fae1f..4ff0b7a83b 100644
--- a/packages/pyright-internal/src/analyzer/typeEvaluatorTypes.ts
+++ b/packages/pyright-internal/src/analyzer/typeEvaluatorTypes.ts
@@ -884,4 +884,5 @@ export interface TypeEvaluator {
         logger: ConsoleInterface
     ) => void;
     typesOverlap: (leftType: Type, rightType: Type, checkEq: boolean) => boolean;
+    markParamAccessed: (param: ParameterNode) => void;
 }
diff --git a/packages/pyright-internal/src/analyzer/typeUtils.ts b/packages/pyright-internal/src/analyzer/typeUtils.ts
index 2b889e4413..26d5d6cf81 100644
--- a/packages/pyright-internal/src/analyzer/typeUtils.ts
+++ b/packages/pyright-internal/src/analyzer/typeUtils.ts
@@ -1423,7 +1423,8 @@ export function isEllipsisType(type: Type): boolean {
     return isAny(type) && type.priv.isEllipsis;
 }
 
-export function isProperty(type: Type) {
+// type guard commented out due to https://github.com/microsoft/TypeScript/issues/15048
+export function isProperty(type: Type) /* : type is ClassType */ {
     return isClassInstance(type) && ClassType.isPropertyClass(type);
 }
 
diff --git a/packages/pyright-internal/src/tests/samples/reportUnusedParameter.py b/packages/pyright-internal/src/tests/samples/reportUnusedParameter.py
index 1a040e6bc3..60dffcff7b 100644
--- a/packages/pyright-internal/src/tests/samples/reportUnusedParameter.py
+++ b/packages/pyright-internal/src/tests/samples/reportUnusedParameter.py
@@ -1,4 +1,4 @@
-from abc import abstractmethod
+from abc import ABC, abstractmethod
 from typing import override
 
 
@@ -23,4 +23,12 @@ def __baz__(self, asdf: int):  # no error, dunder
     def qux(self, __asdf: int):  # error, unused cringe positional argument
         ...
 
-def bar(_value: int): ...
\ No newline at end of file
+def bar(_value: int): ...
+
+class Baz(ABC):
+    @property
+    @abstractmethod
+    def foo(self) -> str:...
+    @foo.setter
+    def foo(self, new_value: str):  # no error, abstract property
+        ...
\ No newline at end of file