From 977887c337f097a723b31ee8b4765a2403d3de9d 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 ++++++++
 packages/pyright-internal/src/analyzer/typeEvaluator.ts   | 1 +
 .../pyright-internal/src/analyzer/typeEvaluatorTypes.ts   | 1 +
 packages/pyright-internal/src/analyzer/typeUtils.ts       | 3 ++-
 4 files changed, 12 insertions(+), 1 deletion(-)

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);
 }