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Merge pull request #21470 from Microsoft/optimizeInstantiation

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Skip unnecessary type and symbol instantiations
This commit is contained in:
Anders Hejlsberg
2018-01-30 06:39:08 -08:00
committed by GitHub
parent 12ebbbc992 e3e849687a
commit 6be98fa1a9
1 changed files with 26 additions and 8 deletions
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34
src/compiler/checker.ts
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@@ -8330,11 +8330,18 @@ namespace ts {
function instantiateList<T>(items: T[], mapper: TypeMapper, instantiator: (item: T, mapper: TypeMapper) => T): T[] {
if (items && items.length) {
const result: T[] = [];
for (const v of items) {
result.push(instantiator(v, mapper));
for (let i = 0; i < items.length; i++) {
const item = items[i];
const mapped = instantiator(item, mapper);
if (item !== mapped) {
const result = i === 0 ? [] : items.slice(0, i);
result.push(mapped);
for (i++; i < items.length; i++) {
result.push(instantiator(items[i], mapper));
}
return result;
}
}
return result;
}
return items;
}
@@ -8456,8 +8463,13 @@ namespace ts {
}
function instantiateSymbol(symbol: Symbol, mapper: TypeMapper): Symbol {
const links = getSymbolLinks(symbol);
if (links.type && !maybeTypeOfKind(links.type, TypeFlags.Object | TypeFlags.TypeVariable | TypeFlags.Index)) {
// If the type of the symbol is already resolved, and if that type could not possibly
// be affected by instantiation, simply return the symbol itself.
return symbol;
}
if (getCheckFlags(symbol) & CheckFlags.Instantiated) {
const links = getSymbolLinks(symbol);
// If symbol being instantiated is itself a instantiation, fetch the original target and combine the
// type mappers. This ensures that original type identities are properly preserved and that aliases
// always reference a non-aliases.
@@ -8600,14 +8612,20 @@ namespace ts {
return getAnonymousTypeInstantiation(<MappedType>type, mapper);
}
if ((<ObjectType>type).objectFlags & ObjectFlags.Reference) {
return createTypeReference((<TypeReference>type).target, instantiateTypes((<TypeReference>type).typeArguments, mapper));
const typeArguments = (<TypeReference>type).typeArguments;
const newTypeArguments = instantiateTypes(typeArguments, mapper);
return newTypeArguments !== typeArguments ? createTypeReference((<TypeReference>type).target, newTypeArguments) : type;
}
}
if (type.flags & TypeFlags.Union && !(type.flags & TypeFlags.Primitive)) {
return getUnionType(instantiateTypes((<UnionType>type).types, mapper), UnionReduction.Literal, type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper));
const types = (<UnionType>type).types;
const newTypes = instantiateTypes(types, mapper);
return newTypes !== types ? getUnionType(newTypes, UnionReduction.Literal, type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper)) : type;
}
if (type.flags & TypeFlags.Intersection) {
return getIntersectionType(instantiateTypes((<IntersectionType>type).types, mapper), type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper));
const types = (<IntersectionType>type).types;
const newTypes = instantiateTypes(types, mapper);
return newTypes !== types ? getIntersectionType(newTypes, type.aliasSymbol, instantiateTypes(type.aliasTypeArguments, mapper)) : type;
}
if (type.flags & TypeFlags.Index) {
return getIndexType(instantiateType((<IndexType>type).type, mapper));