1 files changed, 27 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/modules/duplicate-imports.js b/js/src/jit-test/tests/modules/duplicate-imports.js
new file mode 100644
index 0000000000..fa87ba8ebd
--- /dev/null
+++ b/js/src/jit-test/tests/modules/duplicate-imports.js
@@ -0,0 +1,27 @@
+// Test errors due to duplicate lexically declared names.
+
+load(libdir + "asserts.js");
+
+function testNoError(source) {
+    parseModule(source);
+}
+
+function testSyntaxError(source) {
+    assertThrowsInstanceOf(() => parseModule(source), SyntaxError);
+}
+
+testNoError("import { a } from 'm';");
+testNoError("import { a as b } from 'm';");
+testNoError("import * as a from 'm';");
+testNoError("import a from 'm';");
+
+testSyntaxError("import { a } from 'm'; let a = 1;");
+testSyntaxError("let a = 1; import { a } from 'm';");
+testSyntaxError("import { a } from 'm'; var a = 1;");
+testSyntaxError("var a = 1; import { a } from 'm';");
+testSyntaxError("import { a, b } from 'm'; const b = 1;");
+testSyntaxError("import { a } from 'm'; import { a } from 'm2';");
+testSyntaxError("import { a } from 'm'; import { b as a } from 'm2';");
+testSyntaxError("import { a } from 'm'; import * as a from 'm2';");
+testSyntaxError("import { a } from 'm'; import a from 'm2';");
+