Don't emit __extends if one is already in scope #1356
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| @@ -7886,7 +7886,7 @@ module ts { | |||
| var staticType = <ObjectType>getTypeOfSymbol(symbol); | |||
| var baseTypeNode = getClassBaseTypeNode(node); | |||
| if (baseTypeNode) { | |||
| emitExtends = emitExtends || !isInAmbientContext(node); | |||
| emitExtends = emitExtends || !(isInAmbientContext(node) || resolveName(node.parent, escapeIdentifier('__extends'), SymbolFlags.Value, undefined, undefined)); | |||
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would this work:
module M {
export var __extends = () =>{};
class A { }
class B extends A { }
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Good point. Should we have the emitter handle this, or just say that only a global __extends is valid?
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I can go either ways. limiting it to global __extends seems simple to implement and handles common scenarios.
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please break this into multiple lines. Or provide a helper function for it.
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Addresses #1350 and probably some other suggestions as well.
This changes the "do we need to emit __extends" logic to see if a symbol named
__extendsis already in visible scope at the site of the class declaration.