Resolve bug inferring context type from generic functions in type parameters

Perryvw · Perryvw · commit 165567968a15 · 2024-09-11T17:47:35.000+02:00
diff --git a/src/transformation/utils/function-context.ts b/src/transformation/utils/function-context.ts
@@ -2,7 +2,7 @@ import * as ts from "typescript";
 import { CompilerOptions } from "../../CompilerOptions";
 import { TransformationContext } from "../context";
 import { AnnotationKind, getFileAnnotations, getNodeAnnotations } from "./annotations";
-import { findFirstNodeAbove, getAllCallSignatures, inferAssignedType } from "./typescript";
+import { findFirstNodeAbove, findFirstNonOuterParent, getAllCallSignatures, inferAssignedType } from "./typescript";
 
 export enum ContextType {
     None = 0,
@@ -118,6 +118,13 @@ function computeDeclarationContextType(context: TransformationContext, signature
         return ContextType.Void;
     }
 
+    if (
+        ts.isArrowFunction(signatureDeclaration) &&
+        ts.isCallExpression(findFirstNonOuterParent(signatureDeclaration))
+    ) {
+        return ContextType.Void;
+    }
+
     if (
         ts.isMethodSignature(signatureDeclaration) ||
         ts.isMethodDeclaration(signatureDeclaration) ||
diff --git a/test/unit/functions/validation/validFunctionAssignments.spec.ts b/test/unit/functions/validation/validFunctionAssignments.spec.ts
@@ -248,3 +248,21 @@ test("Does not fail on union type signatures (#896)", () => {
         )
         .expectToHaveNoDiagnostics();
 });
+
+// https://github.com/TypeScriptToLua/TypeScriptToLua/issues/1568
+test("No false positives when using generic functions (#1568)", () => {
+    util.testModule`
+        /** @noSelf */
+        declare namespace Test {
+            export function testCallback<T extends (...args: any[]) => void>(
+                callback: T,
+            ): void;
+            export function testCallback2(
+                callback: (...args: any[]) => void,
+            ): void;
+        }
+
+        Test.testCallback(() => {});
+        Test.testCallback2(() => {});
+    `.expectToHaveNoDiagnostics();
+});
