These are not currently added to the exportedNames list. Let/const bindings will generate a SyntaxError if they duplicate the name of an existing binding, but this is not enough to catch all errors.

Patch to add exported let/const names to the exported names list and add tests.

Comment on attachment 8697245 [details] [diff] [review] check-duplicate-export-let Review of attachment 8697245 [details] [diff] [review]: ----------------------------------------------------------------- ::: js/src/frontend/Parser.cpp @@ +5052,5 @@ > +template<> > +bool > +Parser<SyntaxParseHandler>::addExportNamesForDeclaration(Node node) > +{ > + JS_ALWAYS_FALSE(abortIfSyntaxParser()); MOZ_ALWAYS_FALSE if you would @@ +5276,5 @@ > kid = lexicalDeclaration(YieldIsName, tt == TOK_CONST); > if (!kid) > return null(); > + if (!addExportNamesForDeclaration(kid)) > + return null(); Ah, good catch. ::: js/src/jit-test/tests/modules/duplicate-exports.js @@ +30,5 @@ > +testSyntaxError("export let x, y, z; export let y;"); > +testSyntaxError("export const v = 0; export const v = 0;"); > +testSyntaxError("export const x = 0, y = 0, z = 0; export const y = 0;"); > +testSyntaxError("export var v; export let v;"); > +testSyntaxError("export var v; export const v = 0;"); Could you add one more case testing |export let v; export const v;|?