optimizing varargs on functions passed as parameters (#1042)

tomblind · web-flow · commit 6c7c3366c287 · 2021-07-08T21:13:26.000+02:00
diff --git a/src/transformation/utils/scope.ts b/src/transformation/utils/scope.ts
@@ -93,7 +93,9 @@ export function popScope(context: TransformationContext): Scope {
 }
 
 function isDeclaredInScope(symbol: ts.Symbol, scopeNode: ts.Node) {
-    return symbol?.declarations?.some(d => findFirstNodeAbove(d, (n): n is ts.Node => n === scopeNode));
+    return symbol?.declarations?.some(
+        d => findFirstNodeAbove(d, (n): n is ts.Node => n === scopeNode) && !ts.isParameter(d.parent)
+    );
 }
 
 // Checks for references to local functions which haven't been defined yet,
diff --git a/test/unit/__snapshots__/spread.spec.ts.snap b/test/unit/__snapshots__/spread.spec.ts.snap
@@ -66,6 +66,21 @@ end
 return ____exports"
 `;
 
+exports[`vararg spread optimization curry 1`] = `
+"local ____exports = {}
+function ____exports.__main(self)
+    local function test(self, fn, ...)
+        return fn(nil, ...)
+    end
+    return test(
+        nil,
+        function(____, arg) return arg end,
+        \\"foobar\\"
+    )
+end
+return ____exports"
+`;
+
 exports[`vararg spread optimization finally clause 1`] = `
 "local ____exports = {}
 function ____exports.__main(self)
diff --git a/test/unit/spread.spec.ts b/test/unit/spread.spec.ts
@@ -230,6 +230,17 @@ describe("vararg spread optimization", () => {
             .expectLuaToMatchSnapshot()
             .expectToEqual("b");
     });
+
+    test("curry", () => {
+        util.testFunction`
+            function test<A extends any[]>(fn: (...args: A) => void, ...args: A) {
+                return fn(...args);
+            }
+            return test((arg: string) => arg, "foobar");
+        `
+            .expectLuaToMatchSnapshot()
+            .expectToMatchJsResult();
+    });
 });
 
 describe("vararg spread de-optimization", () => {

Original file line number	Diff line number	Diff line change
`@@ -93,7 +93,9 @@ export function popScope(context: TransformationContext): Scope {`
`93`	`93`	`}`
`94`	`94`
`95`	`95`	`function isDeclaredInScope(symbol: ts.Symbol, scopeNode: ts.Node) {`
`96`		`- return symbol?.declarations?.some(d => findFirstNodeAbove(d, (n): n is ts.Node => n === scopeNode));`
	`96`	`+ return symbol?.declarations?.some(`
	`97`	`+ d => findFirstNodeAbove(d, (n): n is ts.Node => n === scopeNode) && !ts.isParameter(d.parent)`
	`98`	`+ );`
`97`	`99`	`}`
`98`	`100`
`99`	`101`	`// Checks for references to local functions which haven't been defined yet,`