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Optimize checking involving large discriminated union types #42556

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Merged
ahejlsberg merged 18 commits into from
Mar 1, 2021
Merged

Optimize checking involving large discriminated union types #42556

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d15a94f
No array literal subtype reduction when contextual type is present
ahejlsberg Jan 29, 2021
cb2d36e
Accept new baselines
ahejlsberg Jan 29, 2021
216266b
Fast path in relations and filtering of pure discriminated union types
ahejlsberg Jan 30, 2021
9e8f24b
Create maps for mixed unions, but not for small or primitive only unions
ahejlsberg Jan 31, 2021
af9552d
Create many-to-many mapping with certain limits, also use in CFA
ahejlsberg Feb 2, 2021
0510f8a
Use constituent maps in CFA for switch statements, cleanup, add comments
ahejlsberg Feb 3, 2021
6bb2fcb
Merge branch 'master' into fix42522
ahejlsberg Feb 3, 2021
3a57384
Revert change to apparent contextual type / better criteria for map e…
ahejlsberg Feb 4, 2021
6d04025
Deduplicate array literal element types
ahejlsberg Feb 16, 2021
1597be8
Accept new baselines
ahejlsberg Feb 16, 2021
9e2013c
Filter in false case only when discriminant property has unit type
ahejlsberg Feb 17, 2021
7e1b99d
Merge branch 'master' into fix42522
ahejlsberg Feb 17, 2021
0b62483
Only subtype reduce unions with less than 100 distinct types
ahejlsberg Feb 18, 2021
781c1d7
Accept new baselines
ahejlsberg Feb 18, 2021
538b5c8
Caching and quick discriminant checks in subtype reduction
ahejlsberg Feb 19, 2021
3d6dbf4
Accept new baselines
ahejlsberg Feb 19, 2021
d282c70
Merge branch 'master' into fix42522
ahejlsberg Feb 21, 2021
a18aac2
Remove deduplication logic now that subtype reduction was optimized
ahejlsberg Feb 28, 2021
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Remove deduplication logic now that subtype reduction was optimized
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@ahejlsberg
ahejlsberg committed Feb 28, 2021
commit a18aac27c604a85de6dd4f219619870fa5545392
45 changes: 1 addition & 44 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -25215,9 +25215,8 @@ namespace ts {
if (forceTuple || inConstContext || contextualType && forEachType(contextualType, isTupleLikeType)) {
return createArrayLiteralType(createTupleType(elementTypes, elementFlags, /*readonly*/ inConstContext));
}
const deduplicatedTypes = deduplicateObjectOrArrayLiteralTypes(sameMap(elementTypes, (t, i) => elementFlags[i] & ElementFlags.Variadic ? getIndexedAccessTypeOrUndefined(t, numberType) || anyType : t));
return createArrayLiteralType(createArrayType(elementTypes.length ?
getUnionType(deduplicatedTypes, UnionReduction.Subtype) :
getUnionType(sameMap(elementTypes, (t, i) => elementFlags[i] & ElementFlags.Variadic ? getIndexedAccessTypeOrUndefined(t, numberType) || anyType : t), UnionReduction.Subtype) :
strictNullChecks ? implicitNeverType : undefinedWideningType, inConstContext));
}

Expand All @@ -25233,48 +25232,6 @@ namespace ts {
return literalType;

@weswigham weswigham Feb 16, 2021

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As-is, I think this'd intern { set a(x: string) {} } and { get a(){ return ""; } } to the same type, even though the later has a readonly a. Maybe just encoding the symbol flags wholesale in the key will be the most future proof thing, and then you can just join the names with , and not worry about the name length list thing.

@ahejlsberg ahejlsberg Feb 18, 2021

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Yeah, I'll look to make sure we properly preserve that distinction. The name length list is still needed since property names can contain any character, including any separator we might use to separate them.

}

/**
* Replaces all references to structurally equivalent object and array literal types in the given list
* with references to a single one of those types. The process is applied recursively to properties of
* object literals and elements of array literals.
*/
function deduplicateObjectOrArrayLiteralTypes(types: Type[]) {
if (!some(types, isObjectOrArrayLiteralType)) {
return types;
}
const typeMap = new Map<string, Type>();
return sameMap(types, getInternedType);

function getInternedType(type: Type): Type {
if (type.flags & TypeFlags.Union) {
const newTypes = sameMap((<UnionType>type).types, getInternedType);
return newTypes !== (<UnionType>type).types ? getUnionType(newTypes) : type;
}
const key = getLiteralTypeKey(type);
return key ? typeMap.get(key) || (typeMap.set(key, type), type) : type;
}

function getLiteralTypeKey(type: Type): string | undefined {
const objectFlags = getObjectFlags(type);
if (objectFlags & ObjectFlags.ObjectLiteral) {
const props = getPropertiesOfObjectType(type);
const propTypes = map(props, p => getInternedType(getTypeOfSymbol(p)));
const nameLengths = map(props, p => p.flags & SymbolFlags.Optional ? -(<string>p.escapedName).length : (<string>p.escapedName).length);
const nameStrings = map(props, p => <string>p.escapedName);
return `${getTypeListId(propTypes)}|${nameLengths.join(",")}|${nameStrings.join("")}`;
}
if (objectFlags & ObjectFlags.ArrayLiteral) {
if (isArrayType(type)) {
return `${isReadonlyArrayType(type) ? "R" : "A"}${getTypeId(getInternedType(getTypeArguments(type)[0]))}`;
}
if (isTupleType(type)) {
return `T${getTypeId(type.target)}|${getTypeListId(sameMap(getTypeArguments(type), getInternedType))}`;
}
}
return undefined;
}
}

function isNumericName(name: DeclarationName): boolean {
switch (name.kind) {
case SyntaxKind.ComputedPropertyName:
Expand Down