1340148 - Redeclaration of top-level functions should throw SyntaxError in modules

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[André Bargull [:anba]]

Test case:
---
function f() {}
var f;
---

Expected: Throws SyntaxError
Actual: No error

Comment 1

[André Bargull [:anba]]

Attachment: bug1340148.patch

Adding a new DeclarationKind entry seems to be the easiest way to handle this early error restriction.

Comment 2

[André Bargull [:anba]]

Spec bits:

https://tc39.github.io/ecma262/#sec-module-semantics-static-semantics-early-errors
15.2.1.1 Static Semantics: Early Errors
- It is a Syntax Error if the LexicallyDeclaredNames of ModuleItemList contains any duplicate entries. 


https://tc39.github.io/ecma262/#sec-module-semantics-static-semantics-lexicallydeclarednames
15.2.1.11 Static Semantics: LexicallyDeclaredNames
- ModuleItem:StatementListItem
    Return LexicallyDeclaredNames of StatementListItem. 

(Also NOTE 2 in 15.2.1.11)


https://tc39.github.io/ecma262/#sec-block-static-semantics-lexicallydeclarednames
13.2.5 Static Semantics: LexicallyDeclaredNames
- StatementListItem:Declaration
    Return the BoundNames of Declaration.

Comment 3

[Jon Coppeard (:jonco)]

Comment on attachment 8841099 [details] [diff] [review]
bug1340148.patch

Review of attachment 8841099 [details] [diff] [review]:
-----------------------------------------------------------------

I love the exhaustive test.

Comment 4

[André Bargull [:anba]]

Attachment: bug1340148.patch

Updated patch to apply cleanly on inbound, carrying r+ from jonco.

Comment 5

[André Bargull [:anba]]

Try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=1385bc84ccb5564640b4359fc7816a4b924e516e

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/1bc4a653e92e
Disallow function redeclarations at module top level. r=jonco

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/1bc4a653e92e