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Fix optimized vararg spread with casts #1193

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Merged
Perryvw merged 1 commit into from
Dec 21, 2021
Merged

Fix optimized vararg spread with casts #1193

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22 changes: 15 additions & 7 deletions src/transformation/visitors/spread.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -16,8 +16,15 @@ import { isMultiReturnCall } from "./language-extensions/multi";
import { annotationRemoved } from "../utils/diagnostics";
import { isGlobalVarargConstant } from "./language-extensions/vararg";

function skipOuterExpressionParents(node: ts.Node) {
while (ts.isOuterExpression(node)) {
node = node.parent;
}
return node;
}

export function isOptimizedVarArgSpread(context: TransformationContext, symbol: ts.Symbol, identifier: ts.Identifier) {
if (!ts.isSpreadElement(identifier.parent)) {
if (!ts.isSpreadElement(skipOuterExpressionParents(identifier.parent))) {
return false;
}

Expand Down Expand Up @@ -63,20 +70,21 @@ export function isOptimizedVarArgSpread(context: TransformationContext, symbol:

// TODO: Currently it's also used as an array member
export const transformSpreadElement: FunctionVisitor<ts.SpreadElement> = (node, context) => {
if (ts.isIdentifier(node.expression)) {
if (isVarargType(context, node.expression)) {
const tsInnerExpression = ts.skipOuterExpressions(node.expression);
if (ts.isIdentifier(tsInnerExpression)) {
if (isVarargType(context, tsInnerExpression)) {
context.diagnostics.push(annotationRemoved(node, AnnotationKind.Vararg));
}
const symbol = context.checker.getSymbolAtLocation(node.expression);
if (symbol && isOptimizedVarArgSpread(context, symbol, node.expression)) {
const symbol = context.checker.getSymbolAtLocation(tsInnerExpression);
if (symbol && isOptimizedVarArgSpread(context, symbol, tsInnerExpression)) {
return lua.createDotsLiteral(node);
}
}

const innerExpression = context.transformExpression(node.expression);
if (isMultiReturnCall(context, node.expression)) return innerExpression;
if (isMultiReturnCall(context, tsInnerExpression)) return innerExpression;

const type = context.checker.getTypeAtLocation(node.expression);
const type = context.checker.getTypeAtLocation(node.expression); // not ts-inner expression, in case of casts
if (isArrayType(context, type)) {
return createUnpackCall(context, innerExpression, node);
}
Expand Down
12 changes: 9 additions & 3 deletions src/typescript-internal.d.ts
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@@ -1,5 +1,4 @@
import { DiagnosticsProducingTypeChecker } from "./transformation/context";

export {};

declare module "typescript" {
Expand Down Expand Up @@ -31,6 +30,13 @@ declare module "typescript" {

function transformJsx(context: TransformationContext): (x: SourceFile) => SourceFile;

function skipParentheses(node: Expression): Expression;
function skipParentheses(node: Node): Node;
export type OuterExpression =
| ParenthesizedExpression
| TypeAssertion
| AsExpression
| NonNullExpression
| PartiallyEmittedExpression;

function skipOuterExpressions(node: Expression, kinds?: OuterExpressionKinds): Expression;
export function isOuterExpression(node: Node, kinds?: OuterExpressionKinds): node is OuterExpression;
}
15 changes: 15 additions & 0 deletions test/unit/__snapshots__/spread.spec.ts.snap
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Expand Up @@ -17,6 +17,21 @@ end
return ____exports"
`;

exports[`vararg spread optimization With cast 1`] = `
"local ____exports = {}
function ____exports.__main(self)
local function pick(self, ...)
local args = {...}
return args[2]
end
local function test(self, ...)
return pick(nil, ...)
end
return test(nil, \\"a\\", \\"b\\", \\"c\\")
end
return ____exports"
`;

exports[`vararg spread optimization basic use 1`] = `
"local ____exports = {}
function ____exports.__main(self)
Expand Down
12 changes: 12 additions & 0 deletions test/unit/spread.spec.ts
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Expand Up @@ -265,6 +265,18 @@ describe("vararg spread optimization", () => {
.expectLuaToMatchSnapshot()
.expectToMatchJsResult();
});

test("With cast", () => {
util.testFunction`
function pick(...args: any[]) { return args[1]; }
function test<F extends (...args: any)=>any>(...args: Parameters<F>) {
return pick(...(args as any[]));
}
return test<(...args: string[])=>void>("a", "b", "c");
`
.expectLuaToMatchSnapshot()
.expectToMatchJsResult();
});
});

describe("vararg spread de-optimization", () => {
Expand Down