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Made the first-declaration check conservative in the TypeScript transform.

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This commit is contained in:
Daniel Rosenwasser 2017-08-05 00:12:54 -07:00
parent 5cb5cf14de
commit 9f1b747113
2 changed files with 10 additions and 9 deletions
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17
src/compiler/transformers/ts.ts
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@ -2639,9 +2639,6 @@ namespace ts {
/**
* Records that a declaration was emitted in the current scope, if it was the first
* declaration for the provided symbol.
*
* NOTE: if there is ever a transformation above this one, we may not be able to rely
* on symbol names.
*/
function recordEmittedDeclarationInScope(node: Node) {
const name = node.symbol && node.symbol.escapedName;
@ -2657,10 +2654,13 @@ namespace ts {
}
/**
* Determines whether a declaration is the first declaration with the same name emitted
* in the current scope.
* Determines whether a declaration is *could* be the first declaration with
* the same name emitted in the current scope. Only returns false if we are absolutely
* certain a previous declaration has been emitted.
*/
function isFirstEmittedDeclarationInScope(node: Node) {
function isPotentiallyFirstEmittedDeclarationInScope(node: Node) {
// If the node has a named symbol, then we have enough knowledge to determine
// whether a prior declaration has been emitted.
if (currentScopeFirstDeclarationsOfName) {
const name = node.symbol && node.symbol.escapedName;
if (name) {
@ -2668,7 +2668,8 @@ namespace ts {
}
}
return false;
// Otherwise, we can't be sure. For example, this node could be synthetic.
return true;
}
/**
@ -2690,7 +2691,7 @@ namespace ts {
setOriginalNode(statement, node);
recordEmittedDeclarationInScope(node);
if (isFirstEmittedDeclarationInScope(node)) {
if (isPotentiallyFirstEmittedDeclarationInScope(node)) {
// Adjust the source map emit to match the old emitter.
if (node.kind === SyntaxKind.EnumDeclaration) {
setSourceMapRange(statement.declarationList, node);

2
src/harness/unittests/transform.ts
View file

@ -99,7 +99,7 @@ namespace ts {
}
};
}
})
});
});
}