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Cache 'any' instantiations for faster conditional type resolution

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This commit is contained in:
Anders Hejlsberg 2018-01-27 10:07:24 -08:00
parent fa6c4b79dd
commit edffb12054
2 changed files with 11 additions and 6 deletions
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15
src/compiler/checker.ts
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@ -8104,8 +8104,10 @@ namespace ts {
function getConditionalType(checkType: Type, baseExtendsType: Type, baseTrueType: Type, baseFalseType: Type, inferTypeParameters: TypeParameter[], target: ConditionalType, mapper: TypeMapper, aliasSymbol?: Symbol, baseAliasTypeArguments?: Type[]): Type {
// Instantiate extends type without instantiating any 'infer T' type parameters
const extendsType = instantiateType(baseExtendsType, mapper);
// Return falseType for a definitely false extends check
if (!isTypeAssignableTo(instantiateType(checkType, anyMapper), instantiateType(extendsType, constraintMapper))) {
// Return falseType for a definitely false extends check. We check an instantations of the two
// types with type parameters mapped to any, the most permissive instantiations possible. If those
// are not related, then no instatiations will be and we can just return the false branch type.
if (!isTypeAssignableTo(getAnyInstantiation(checkType), getAnyInstantiation(extendsType))) {
return instantiateType(baseFalseType, mapper);
}
// The check could be true for some instantiation
@ -8561,10 +8563,6 @@ namespace ts {
return type.flags & TypeFlags.TypeParameter ? anyType : type;
}
function constraintMapper(type: Type) {
return type.flags & TypeFlags.TypeParameter ? getConstraintOfTypeParameter(<TypeParameter>type) || anyType : type;
}
function cloneTypeParameter(typeParameter: TypeParameter): TypeParameter {
const result = <TypeParameter>createType(TypeFlags.TypeParameter);
result.symbol = typeParameter.symbol;
@ -8808,6 +8806,11 @@ namespace ts {
return type;
}
function getAnyInstantiation(type: Type) {
return type.flags & (TypeFlags.Primitive | TypeFlags.Any | TypeFlags.Never) ? type :
type.resolvedAnyInstantiation || (type.resolvedAnyInstantiation = instantiateType(type, anyMapper));
}
function instantiateIndexInfo(info: IndexInfo, mapper: TypeMapper): IndexInfo {
return info && createIndexInfo(instantiateType(info.type, mapper), info.isReadonly, info.declaration);
}

2
src/compiler/types.ts
View File

@ -3557,6 +3557,8 @@ namespace ts {
pattern?: DestructuringPattern; // Destructuring pattern represented by type (if any)
aliasSymbol?: Symbol; // Alias associated with type
aliasTypeArguments?: Type[]; // Alias type arguments (if any)
/* @internal */
resolvedAnyInstantiation?: Type; // Instantiation with type parameters mapped to any
}
/* @internal */