Merge pull request #1023 from anba/redeclaration

Lexical redeclarations in block- and switch-statements

Background feedback from @anba:

In https://tc39.github.io/ecma262/#sec-switch-statement-static-semantics-lexicallydeclarednames, all lexically declared names from the different case clauses are combined.
For each case clause, the LexicallyDeclaredNames definition from https://tc39.github.io/ecma262/#sec-block-static-semantics-lexicallydeclarednames applies, which has:

```
StatementListItem : Declaration
  1. Return the BoundNames of Declaration.
```

And in https://tc39.github.io/ecma262/#prod-Declaration we've got:

```
Declaration[Yield, Await] : HoistableDeclaration[?Yield, ?Await, ~Default]
```

And in https://tc39.github.io/ecma262/#prod-HoistableDeclaration:

```
HoistableDeclaration[Yield, Await, Default] : FunctionDeclaration[?Yield, ?Await, ?Default]
```

And the BoundNames of a FunctionDeclaration is its BindingIdentifier https://tc39.github.io/ecma262/#sec-function-definitions-static-semantics-boundnames.

And there's also B3.3.5 (https://tc39.github.io/ecma262/#sec-switch-duplicates-allowed-static-semantics) which allows duplicate FunctionDeclarations in sloppy mode in switch-statements.

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-async-function-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/async-function-declaration-attempt-to-
+name: AsyncFunctionDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [async-functions]
+---*/
+
+{ async function f() {} /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-async-generator-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/async-generator-declaration-attempt-to-
+name: AsyncGeneratorDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [async-iteration]
+---*/
+
+{ async function* f() {} /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-class-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/class-declaration-attempt-to-
+name: ClassDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ class f {} /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-const-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/const-declaration-attempt-to-
+name: LexicalDeclaration (const) in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ const f = 0; /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-function-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/function-declaration-attempt-to-
+name: FunctionDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [onlyStrict]
+---*/
+
+{ function f() {} /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-generator-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/generator-declaration-attempt-to-
+name: GeneratorDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ function* f() {} /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-let-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/let-declaration-attempt-to-
+name: LexicalDeclaration (let) in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if the LexicallyDeclaredNames of StatementList contains
+  any duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ let f; /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/block-attempt-to-redeclare-var-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/var-declaration-attempt-to-
+name: VariableDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if any element of the LexicallyDeclaredNames of
+  StatementList also occurs in the VarDeclaredNames of StatementList.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ var f; /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-async-function-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/async-function-declaration-attempt-to-
+name: AsyncFunctionDeclaration in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [async-functions]
+---*/
+
+switch (0) { case 1: async function f() {} default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-async-generator-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/async-generator-declaration-attempt-to-
+name: AsyncGeneratorDeclaration in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [async-iteration]
+---*/
+
+switch (0) { case 1: async function* f() {} default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-class-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/class-declaration-attempt-to-
+name: ClassDeclaration in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+switch (0) { case 1: class f {} default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-const-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/const-declaration-attempt-to-
+name: LexicalDeclaration (const) in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+switch (0) { case 1: const f = 0; default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-function-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/function-declaration-attempt-to-
+name: FunctionDeclaration in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [onlyStrict]
+---*/
+
+switch (0) { case 1: function f() {} default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-generator-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/generator-declaration-attempt-to-
+name: GeneratorDeclaration in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+switch (0) { case 1: function* f() {} default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-let-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/let-declaration-attempt-to-
+name: LexicalDeclaration (let) in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if the LexicallyDeclaredNames of CaseBlock contains any
+  duplicate entries.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+switch (0) { case 1: let f; default: /*{ body }*/ }

src/declarations/redeclare-allow-sloppy-function/switch-attempt-to-redeclare-var-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/statements/switch/syntax/redeclaration/var-declaration-attempt-to-
+name: VariableDeclaration in SwitchStatement
+esid: sec-switch-statement-static-semantics-early-errors
+info: |
+  SwitchStatement : switch ( Expression ) CaseBlock
+
+  It is a Syntax Error if any element of the LexicallyDeclaredNames of
+  CaseBlock also occurs in the VarDeclaredNames of CaseBlock.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+switch (0) { case 1: var f; default: /*{ body }*/ }

src/declarations/redeclare-allow-var/block-attempt-to-redeclare-async-function-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/async-function-declaration-attempt-to-
+name: AsyncFunctionDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if any element of the LexicallyDeclaredNames of
+  StatementList also occurs in the VarDeclaredNames of StatementList.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [async-functions]
+---*/
+
+{ async function f() {} /*{ body }*/ }

src/declarations/redeclare-allow-var/block-attempt-to-redeclare-async-generator-declaration.template

@@ -0,0 +1,19 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/async-generator-declaration-attempt-to-
+name: AsyncGeneratorDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if any element of the LexicallyDeclaredNames of
+  StatementList also occurs in the VarDeclaredNames of StatementList.
+negative:
+  phase: early
+  type: SyntaxError
+flags: [async-iteration]
+---*/
+
+{ async function* f() {} /*{ body }*/ }

src/declarations/redeclare-allow-var/block-attempt-to-redeclare-class-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/class-declaration-attempt-to-
+name: ClassDeclaration in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if any element of the LexicallyDeclaredNames of
+  StatementList also occurs in the VarDeclaredNames of StatementList.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ class f {} /*{ body }*/ }

src/declarations/redeclare-allow-var/block-attempt-to-redeclare-const-declaration.template

@@ -0,0 +1,18 @@
+// Copyright (C) 2017 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+path: language/block-scope/syntax/redeclaration/const-declaration-attempt-to-
+name: LexicalDeclaration (const) in BlockStatement
+esid: sec-block-static-semantics-early-errors
+info: |
+  Block : { StatementList }
+
+  It is a Syntax Error if any element of the LexicallyDeclaredNames of
+  StatementList also occurs in the VarDeclaredNames of StatementList.
+negative:
+  phase: early
+  type: SyntaxError
+---*/
+
+{ const f = 0; /*{ body }*/ }