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disallow recursive references for block-scoped bindings

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This commit is contained in:
Vladimir Matveev
2015-03-11 16:54:18 -07:00
parent 76dcfb660b
commit 751b1aee16
8 changed files with 159 additions and 41 deletions
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44
src/compiler/checker.ts
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@@ -439,7 +439,33 @@ module ts {
var declaration = forEach(result.declarations, d => isBlockOrCatchScoped(d) ? d : undefined);
Debug.assert(declaration !== undefined, "Block-scoped variable declaration is undefined");
if (!isDefinedBefore(declaration, errorLocation)) {
// first check if usage is lexically located after the declaration
var isUsedBeforeDeclaration = !isDefinedBefore(declaration, errorLocation);
if (!isUsedBeforeDeclaration) {
// lexical check succedded however code still can be illegal.
// - block scoped variables cannot be used in its initializers
// let x = x; // illegal but usage is lexically after definition
// - in ForIn/ForOf statements variable cannot be contained in expression part
// for (let x in x)
// for (let x of x)
// climb up to the variable declaration skipping binding patterns
var variableDeclaration = <VariableDeclaration>getAncestor(declaration, SyntaxKind.VariableDeclaration);
var container = getEnclosingBlockScopeContainer(variableDeclaration);
if (variableDeclaration.parent.parent.kind === SyntaxKind.VariableStatement ||
variableDeclaration.parent.parent.kind === SyntaxKind.ForStatement) {
// variable statement/for statement case, use site should not be inside initializer
isUsedBeforeDeclaration = isChildNode(errorLocation, variableDeclaration.initializer, container);
}
else if (variableDeclaration.parent.parent.kind === SyntaxKind.ForOfStatement ||
variableDeclaration.parent.parent.kind === SyntaxKind.ForInStatement) {
// ForIn/ForOf case - use site should not be used in expression part
isUsedBeforeDeclaration = isChildNode(errorLocation, (<ForInStatement>variableDeclaration.parent.parent).expression, container);
}
}
if (isUsedBeforeDeclaration) {
error(errorLocation, Diagnostics.Block_scoped_variable_0_used_before_its_declaration, declarationNameToString(declaration.name));
}
}
@@ -447,6 +473,22 @@ module ts {
return result;
}
/* Starting from 'initial' node walk up the parent chain until 'stopAt' node is reached.
* If at any point current node is equal to 'parent' node - return true.
* Return false if 'stopAt' node is reached.
*/
function isChildNode(initial: Node, parent: Node, stopAt: Node): boolean {
if (!parent) {
return false;
}
for (var current = initial; current && current !== stopAt; current = current.parent) {
if (current === parent) {
return true;
}
}
return false;
}
// An alias symbol is created by one of the following declarations:
// import <symbol> = ...
// import <symbol> from ...

28
src/compiler/emitter.ts
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@@ -4116,34 +4116,6 @@ module ts {
}
}
function getEnclosingBlockScopeContainer(node: Node): Node {
var current = node;
while (current) {
if (isFunctionLike(current)) {
return current;
}
switch (current.kind) {
case SyntaxKind.SourceFile:
case SyntaxKind.CaseBlock:
case SyntaxKind.CatchClause:
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.ForStatement:
case SyntaxKind.ForInStatement:
case SyntaxKind.ForOfStatement:
return current;
case SyntaxKind.Block:
// function block is not considered block-scope container
// see comment in binder.ts: bind(...), case for SyntaxKind.Block
if (!isFunctionLike(current.parent)) {
return current;
}
}
current = current.parent;
}
}
function getCombinedFlagsForIdentifier(node: Identifier): NodeFlags {
if (!node.parent || (node.parent.kind !== SyntaxKind.VariableDeclaration && node.parent.kind !== SyntaxKind.BindingElement)) {
return 0;

27
src/compiler/utilities.ts
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@@ -203,6 +203,33 @@ module ts {
isCatchClauseVariableDeclaration(declaration);
}
export function getEnclosingBlockScopeContainer(node: Node): Node {
var current = node;
while (current) {
if (isFunctionLike(current)) {
return current;
}
switch (current.kind) {
case SyntaxKind.SourceFile:
case SyntaxKind.CaseBlock:
case SyntaxKind.CatchClause:
case SyntaxKind.ModuleDeclaration:
case SyntaxKind.ForStatement:
case SyntaxKind.ForInStatement:
case SyntaxKind.ForOfStatement:
return current;
case SyntaxKind.Block:
// function block is not considered block-scope container
// see comment in binder.ts: bind(...), case for SyntaxKind.Block
if (!isFunctionLike(current.parent)) {
return current;
}
}
current = current.parent;
}
}
export function isCatchClauseVariableDeclaration(declaration: Declaration) {
return declaration &&
declaration.kind === SyntaxKind.VariableDeclaration &&

10
tests/baselines/reference/for-of55.errors.txt Normal file
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@@ -0,0 +1,10 @@
tests/cases/conformance/es6/for-ofStatements/for-of55.ts(2,15): error TS2448: Block-scoped variable 'v' used before its declaration.
==== tests/cases/conformance/es6/for-ofStatements/for-of55.ts (1 errors) ====
let v = [1];
for (let v of v) {
~
!!! error TS2448: Block-scoped variable 'v' used before its declaration.
v;
}

12
tests/baselines/reference/for-of55.types
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@@ -1,12 +0,0 @@
=== tests/cases/conformance/es6/for-ofStatements/for-of55.ts ===
let v = [1];
>v : number[]
>[1] : number[]
for (let v of v) {
>v : any
>v : any
v;
>v : any
}

40
tests/baselines/reference/recursiveLetConst.errors.txt Normal file
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@@ -0,0 +1,40 @@
tests/cases/compiler/recursiveLetConst.ts(2,9): error TS2448: Block-scoped variable 'x' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(3,12): error TS2448: Block-scoped variable 'x1' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(4,11): error TS2448: Block-scoped variable 'y' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(5,14): error TS2448: Block-scoped variable 'y1' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(6,14): error TS2448: Block-scoped variable 'v' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(7,16): error TS2448: Block-scoped variable 'v' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(8,15): error TS2448: Block-scoped variable 'v' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(9,15): error TS2448: Block-scoped variable 'v' used before its declaration.
tests/cases/compiler/recursiveLetConst.ts(10,17): error TS2448: Block-scoped variable 'v' used before its declaration.
==== tests/cases/compiler/recursiveLetConst.ts (9 errors) ====
'use strict'
let x = x + 1;
~
!!! error TS2448: Block-scoped variable 'x' used before its declaration.
let [x1] = x1 + 1;
~~
!!! error TS2448: Block-scoped variable 'x1' used before its declaration.
const y = y + 2;
~
!!! error TS2448: Block-scoped variable 'y' used before its declaration.
const [y1] = y1 + 1;
~~
!!! error TS2448: Block-scoped variable 'y1' used before its declaration.
for (let v = v; ; ) { }
~
!!! error TS2448: Block-scoped variable 'v' used before its declaration.
for (let [v] = v; ;) { }
~
!!! error TS2448: Block-scoped variable 'v' used before its declaration.
for (let v in v) { }
~
!!! error TS2448: Block-scoped variable 'v' used before its declaration.
for (let v of v) { }
~
!!! error TS2448: Block-scoped variable 'v' used before its declaration.
for (let [v] of v) { }
~
!!! error TS2448: Block-scoped variable 'v' used before its declaration.

28
tests/baselines/reference/recursiveLetConst.js Normal file
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@@ -0,0 +1,28 @@
//// [recursiveLetConst.ts]
'use strict'
let x = x + 1;
let [x1] = x1 + 1;
const y = y + 2;
const [y1] = y1 + 1;
for (let v = v; ; ) { }
for (let [v] = v; ;) { }
for (let v in v) { }
for (let v of v) { }
for (let [v] of v) { }
//// [recursiveLetConst.js]
'use strict';
let x = x + 1;
let [x1] = x1 + 1;
const y = y + 2;
const [y1] = y1 + 1;
for (let v = v;;) {
}
for (let [v] = v;;) {
}
for (let v in v) {
}
for (let v of v) {
}
for (let [v] of v) {
}

11
tests/cases/compiler/recursiveLetConst.ts Normal file
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@@ -0,0 +1,11 @@
// @target:es6
'use strict'
let x = x + 1;
let [x1] = x1 + 1;
const y = y + 2;
const [y1] = y1 + 1;
for (let v = v; ; ) { }
for (let [v] = v; ;) { }
for (let v in v) { }
for (let v of v) { }
for (let [v] of v) { }