From 1e2d4d646dc1bd9b94bd164bf2450e6bab1ab24f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Sun, 29 Dec 2024 21:29:38 +0100
Subject: [PATCH] Fixed inherited JSDoc lookup on static properties of classes
 with symbol-less base types

---
 src/compiler/checker.ts                       |  1 +
 src/compiler/types.ts                         |  1 +
 src/services/services.ts                      | 11 ++++--
 ...InfoJsDocNoStaticVsInstanceMethodMixup1.ts | 26 ++++++++++++++
 .../quickInfoJsDocOverridesWithMixin1.ts      | 35 +++++++++++++++++++
 5 files changed, 71 insertions(+), 3 deletions(-)
 create mode 100644 tests/cases/fourslash/quickInfoJsDocNoStaticVsInstanceMethodMixup1.ts
 create mode 100644 tests/cases/fourslash/quickInfoJsDocOverridesWithMixin1.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 80b61edd3657a..0a292e5029acc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1621,6 +1621,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             return getSymbolsOfParameterPropertyDeclaration(parameter, escapeLeadingUnderscores(parameterName));
         },
         getDeclaredTypeOfSymbol,
+        getBaseConstructorTypeOfClass,
         getPropertiesOfType,
         getPropertyOfType: (type, name) => getPropertyOfType(type, escapeLeadingUnderscores(name)),
         getPrivateIdentifierPropertyOfType: (leftType: Type, name: string, location: Node) => {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 49938f0fc8249..5d9d6954d9af4 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -5055,6 +5055,7 @@ export interface TypeChecker {
     getTypeOfSymbolAtLocation(symbol: Symbol, node: Node): Type;
     getTypeOfSymbol(symbol: Symbol): Type;
     getDeclaredTypeOfSymbol(symbol: Symbol): Type;
+    /** @internal */ getBaseConstructorTypeOfClass(type: InterfaceType): Type;
     getPropertiesOfType(type: Type): Symbol[];
     getPropertyOfType(type: Type, propertyName: string): Symbol | undefined;
     getPrivateIdentifierPropertyOfType(leftType: Type, name: string, location: Node): Symbol | undefined;
diff --git a/src/services/services.ts b/src/services/services.ts
index fb5e9a0857929..1e8562a8d39f2 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -1051,11 +1051,16 @@ function findBaseOfDeclaration<T>(checker: TypeChecker, declaration: Declaration
     const classOrInterfaceDeclaration = declaration.parent?.kind === SyntaxKind.Constructor ? declaration.parent.parent : declaration.parent;
     if (!classOrInterfaceDeclaration) return;
 
-    const isStaticMember = hasStaticModifier(declaration);
+    if (hasStaticModifier(declaration)) {
+        const classType = checker.getTypeAtLocation(classOrInterfaceDeclaration);
+        Debug.assert(classType.isClassOrInterface());
+        const staticBaseType = checker.getBaseConstructorTypeOfClass(classType);
+        const symbol = checker.getPropertyOfType(staticBaseType, declaration.symbol.name);
+        return symbol ? cb(symbol) : undefined;
+    }
     return firstDefined(getAllSuperTypeNodes(classOrInterfaceDeclaration), superTypeNode => {
         const baseType = checker.getTypeAtLocation(superTypeNode);
-        const type = isStaticMember && baseType.symbol ? checker.getTypeOfSymbol(baseType.symbol) : baseType;
-        const symbol = checker.getPropertyOfType(type, declaration.symbol.name);
+        const symbol = checker.getPropertyOfType(baseType, declaration.symbol.name);
         return symbol ? cb(symbol) : undefined;
     });
 }
diff --git a/tests/cases/fourslash/quickInfoJsDocNoStaticVsInstanceMethodMixup1.ts b/tests/cases/fourslash/quickInfoJsDocNoStaticVsInstanceMethodMixup1.ts
new file mode 100644
index 0000000000000..35e2921c2c652
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoJsDocNoStaticVsInstanceMethodMixup1.ts
@@ -0,0 +1,26 @@
+///<reference path="fourslash.ts" />
+
+//// declare class BaseClass {
+////   /** some documentation for instance method */
+////   method(): string;
+//// }
+////
+//// type AnyConstructor = abstract new (...args: any[]) => object;
+////
+//// function Mix<T extends AnyConstructor>(BaseClass: T) {
+////   abstract class MixinClass extends BaseClass {
+////     constructor(...args: any[]) {
+////       super(...args);
+////     }
+////   }
+////
+////   return MixinClass;
+//// }
+////
+//// declare class Mixed extends Mix(BaseClass) {
+////   static method(): string;
+//// }
+////
+//// Mixed.method/*1*/;
+
+verify.quickInfoAt("1", "(method) Mixed.method(): string", undefined);
\ No newline at end of file
diff --git a/tests/cases/fourslash/quickInfoJsDocOverridesWithMixin1.ts b/tests/cases/fourslash/quickInfoJsDocOverridesWithMixin1.ts
new file mode 100644
index 0000000000000..8794719dae44d
--- /dev/null
+++ b/tests/cases/fourslash/quickInfoJsDocOverridesWithMixin1.ts
@@ -0,0 +1,35 @@
+///<reference path="fourslash.ts" />
+
+//// declare class BaseClass {
+////   /** some documentation for static method */
+////   static staticMethod(): number;
+////
+////   /** some documentation for instance method */
+////   instanceMethod(): string;
+//// }
+////
+//// type AnyConstructor = abstract new (...args: any[]) => object;
+////
+//// function Mix<T extends AnyConstructor>(BaseClass: T) {
+////   abstract class MixinClass extends BaseClass {
+////     constructor(...args: any[]) {
+////       super(...args);
+////     }
+////   }
+////
+////   return MixinClass;
+//// }
+////
+//// declare class Mixed extends Mix(BaseClass) {
+////   static staticMethod(): number;
+////
+////   instanceMethod(): string;
+//// }
+////
+//// Mixed.staticMethod/*1*/;
+////
+//// const m = new Mixed();
+//// m.instanceMethod/*2*/;
+
+verify.quickInfoAt("1", "(method) Mixed.staticMethod(): number", "some documentation for static method");
+verify.quickInfoAt("2", "(method) Mixed.instanceMethod(): string", "some documentation for instance method");
\ No newline at end of file