1353691 - Report SyntaxError when arrow function has await-identifier in async function context.

1 files changed, 94 insertions, 0 deletions

diff --git a/js/src/tests/ecma_2017/AsyncFunctions/await-in-arrow-parameters.js b/js/src/tests/ecma_2017/AsyncFunctions/await-in-arrow-parameters.js
new file mode 100644
index 0000000000..ebb4ea9dac
--- /dev/null
+++ b/js/src/tests/ecma_2017/AsyncFunctions/await-in-arrow-parameters.js
@@ -0,0 +1,94 @@
+var ieval = eval;
+var AsyncFunction = async function(){}.constructor;
+
+var functionContext = {
+    Function: {
+        constructor: Function,
+        toSourceBody: code => `function f() { ${code} }`,
+        toSourceParameter: code => `function f(x = ${code}) { }`,
+    },
+    AsyncFunction: {
+        constructor: AsyncFunction,
+        toSourceBody: code => `async function f() { ${code} }`,
+        toSourceParameter: code => `async function f(x = ${code}) { }`,
+    },
+};
+
+function assertSyntaxError(kind, code) {
+    var {constructor, toSourceBody, toSourceParameter} = functionContext[kind];
+    var body = toSourceBody(code);
+    var parameter = toSourceParameter(code);
+
+    assertThrowsInstanceOf(() => { constructor(code); }, SyntaxError, constructor.name + ":" + code);
+    assertThrowsInstanceOf(() => { constructor(`x = ${code}`, ""); }, SyntaxError, constructor.name + ":" + code);
+
+    assertThrowsInstanceOf(() => { eval(body); }, SyntaxError, "eval:" + body);
+    assertThrowsInstanceOf(() => { ieval(body); }, SyntaxError, "indirect eval:" + body);
+
+    assertThrowsInstanceOf(() => { eval(parameter); }, SyntaxError, "eval:" + parameter);
+    assertThrowsInstanceOf(() => { ieval(parameter); }, SyntaxError, "indirect eval:" + parameter);
+}
+
+function assertNoSyntaxError(kind, code) {
+    var {constructor, toSourceBody, toSourceParameter} = functionContext[kind];
+    var body = toSourceBody(code);
+    var parameter = toSourceParameter(code);
+
+    constructor(code);
+    constructor(`x = ${code}`, "");
+
+    eval(body);
+    ieval(body);
+
+    eval(parameter);
+    ieval(parameter);
+}
+
+function assertSyntaxErrorAsync(code) {
+    assertNoSyntaxError("Function", code);
+    assertSyntaxError("AsyncFunction", code);
+}
+
+function assertSyntaxErrorBoth(code) {
+    assertSyntaxError("Function", code);
+    assertSyntaxError("AsyncFunction", code);
+}
+
+
+// Bug 1353691
+// |await| expression is invalid in arrow functions in async-context.
+// |await/r/g| first parses as |AwaitExpression RegularExpressionLiteral|, when reparsing the
+// arrow function, it is parsed as |IdentRef DIV IdentRef DIV IdentRef|. We need to ensure in this
+// case, that we still treat |await| as a keyword and hence throw a SyntaxError.
+assertSyntaxErrorAsync("(a = await/r/g) => {}");
+assertSyntaxErrorBoth("async(a = await/r/g) => {}");
+
+// Also applies when nesting arrow functions.
+assertSyntaxErrorAsync("(a = (b = await/r/g) => {}) => {}");
+assertSyntaxErrorBoth("async(a = (b = await/r/g) => {}) => {}");
+assertSyntaxErrorBoth("(a = async(b = await/r/g) => {}) => {}");
+assertSyntaxErrorBoth("async(a = async(b = await/r/g) => {}) => {}");
+
+
+// Bug 1355860
+// |await| cannot be used as rest-binding parameter in arrow functions in async-context.
+assertSyntaxErrorAsync("(...await) => {}");
+assertSyntaxErrorBoth("async(...await) => {}");
+
+assertSyntaxErrorAsync("(a, ...await) => {}");
+assertSyntaxErrorBoth("async(a, ...await) => {}");
+
+// Also test nested arrow functions.
+assertSyntaxErrorAsync("(a = (...await) => {}) => {}");
+assertSyntaxErrorBoth("(a = async(...await) => {}) => {}");
+assertSyntaxErrorBoth("async(a = (...await) => {}) => {}");
+assertSyntaxErrorBoth("async(a = async(...await) => {}) => {}");
+
+assertSyntaxErrorAsync("(a = (b, ...await) => {}) => {}");
+assertSyntaxErrorBoth("(a = async(b, ...await) => {}) => {}");
+assertSyntaxErrorBoth("async(a = (b, ...await) => {}) => {}");
+assertSyntaxErrorBoth("async(a = async(b, ...await) => {}) => {}");
+
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);