1 files changed, 94 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/modules/function-redeclaration.js b/js/src/jit-test/tests/modules/function-redeclaration.js
new file mode 100644
index 0000000000..b84704641d
--- /dev/null
+++ b/js/src/jit-test/tests/modules/function-redeclaration.js
@@ -0,0 +1,94 @@
+load(libdir + "asserts.js");
+
+var functionDeclarations = [
+    "function f(){}",
+    "function* f(){}",
+    "async function f(){}",
+];
+
+var varDeclarations = [
+    "var f",
+    "{ var f; }",
+    "for (var f in null);",
+    "for (var f of null);",
+    "for (var f; ;);",
+];
+
+var lexicalDeclarations = [
+    "let f;",
+    "const f = 0;",
+    "class f {};",
+];
+
+var imports = [
+    "import f from '';",
+    "import f, {} from '';",
+    "import d, {f} from '';",
+    "import d, {f as f} from '';",
+    "import d, {foo as f} from '';",
+    "import f, * as d from '';",
+    "import d, * as f from '';",
+    "import {f} from '';",
+    "import {f as f} from '';",
+    "import {foo as f} from '';",
+    "import* as f from '';",
+];
+
+var exports = [
+    "export var f;",
+    ...functionDeclarations.map(fn => `export ${fn};`),
+    ...lexicalDeclarations.map(ld => `export ${ld};`),
+    ...functionDeclarations.map(fn => `export default ${fn};`),
+    "export default class f {};",
+];
+
+var redeclarations = [
+    ...functionDeclarations,
+    ...varDeclarations,
+    ...lexicalDeclarations,
+    ...imports,
+    ...exports,
+];
+
+var noredeclarations = [
+    ...functionDeclarations.map(fn => `{ ${fn} }`),
+    ...lexicalDeclarations.map(ld => `{ ${ld} }`),
+    ...["let", "const"].map(ld => `for (${ld} f in null);`),
+    ...["let", "const"].map(ld => `for (${ld} f of null);`),
+    ...["let", "const"].map(ld => `for (${ld} f = 0; ;);`),
+    "export {f};",
+    "export {f as f};",
+    "export {foo as f}; var foo;",
+    "export {f} from '';",
+    "export {f as f} from '';",
+    "export {foo as f} from '';",
+];
+
+for (var decl of functionDeclarations) {
+    for (var redecl of redeclarations) {
+        assertThrowsInstanceOf(() => {
+            parseModule(`
+                ${decl}
+                ${redecl}
+            `);
+        }, SyntaxError);
+
+        assertThrowsInstanceOf(() => {
+            parseModule(`
+                ${redecl}
+                ${decl}
+            `);
+        }, SyntaxError);
+    }
+
+    for (var redecl of noredeclarations) {
+        parseModule(`
+            ${decl}
+            ${redecl}
+        `);
+        parseModule(`
+            ${redecl}
+            ${decl}
+        `);
+    }
+}