microsoft/TypeScript
1
0
Fork 0
mirror of https://github.com/microsoft/TypeScript.git synced 2026-07-01 11:42:55 -05:00
Code Issues Packages Projects Releases 212 Wiki Activity

Properly reset type guards in loops

Browse Source
This commit is contained in:
Anders Hejlsberg
2016-07-29 07:54:19 -07:00
parent 878cf85438
commit 3e3b80826f
1 changed files with 18 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
src/compiler/checker.ts
View File

@@ -7764,16 +7764,17 @@ namespace ts {
}
function isMatchingReference(source: Node, target: Node): boolean {
if (source.kind === target.kind) {
switch (source.kind) {
case SyntaxKind.Identifier:
return getResolvedSymbol(<Identifier>source) === getResolvedSymbol(<Identifier>target);
case SyntaxKind.ThisKeyword:
return true;
case SyntaxKind.PropertyAccessExpression:
return (<PropertyAccessExpression>source).name.text === (<PropertyAccessExpression>target).name.text &&
isMatchingReference((<PropertyAccessExpression>source).expression, (<PropertyAccessExpression>target).expression);
}
switch (source.kind) {
case SyntaxKind.Identifier:
return target.kind === SyntaxKind.Identifier && getResolvedSymbol(<Identifier>source) === getResolvedSymbol(<Identifier>target) ||
(target.kind === SyntaxKind.VariableDeclaration || target.kind === SyntaxKind.BindingElement) &&
getExportSymbolOfValueSymbolIfExported(getResolvedSymbol(<Identifier>source)) === getSymbolOfNode(target);
case SyntaxKind.ThisKeyword:
return target.kind === SyntaxKind.ThisKeyword;
case SyntaxKind.PropertyAccessExpression:
return target.kind === SyntaxKind.PropertyAccessExpression &&
(<PropertyAccessExpression>source).name.text === (<PropertyAccessExpression>target).name.text &&
isMatchingReference((<PropertyAccessExpression>source).expression, (<PropertyAccessExpression>target).expression);
}
return false;
}
@@ -8031,6 +8032,12 @@ namespace ts {
getInitialTypeOfBindingElement(<BindingElement>node);
}
function getInitialOrAssignedType(node: VariableDeclaration | BindingElement | Expression) {
return node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement ?
getInitialType(<VariableDeclaration | BindingElement>node) :
getAssignedType(<Expression>node);
}
function getReferenceCandidate(node: Expression): Expression {
switch (node.kind) {
case SyntaxKind.ParenthesizedExpression:
@@ -8153,19 +8160,9 @@ namespace ts {
const node = flow.node;
// Assignments only narrow the computed type if the declared type is a union type. Thus, we
// only need to evaluate the assigned type if the declared type is a union type.
if ((node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement) &&
reference.kind === SyntaxKind.Identifier &&
getExportSymbolOfValueSymbolIfExported(getResolvedSymbol(<Identifier>reference)) === getSymbolOfNode(node)) {
return declaredType.flags & TypeFlags.Union ?
getAssignmentReducedType(<UnionType>declaredType, getInitialType(<VariableDeclaration | BindingElement>node)) :
declaredType;
}
// If the node is not a variable declaration or binding element, it is an identifier
// or a dotted name that is the target of an assignment. If we have a match, reduce
// the declared type by the assigned type.
if (isMatchingReference(reference, node)) {
return declaredType.flags & TypeFlags.Union ?
getAssignmentReducedType(<UnionType>declaredType, getAssignedType(<Expression>node)) :
getAssignmentReducedType(<UnionType>declaredType, getInitialOrAssignedType(node)) :
declaredType;
}
// We didn't have a direct match. However, if the reference is a dotted name, this