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Merge pull request #25408 from Microsoft/contextualTupleTypes

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Infer tuple types for contextually typed rest parameters
This commit is contained in:
Anders Hejlsberg
2018-07-03 14:02:48 -10:00
committed by GitHub
parent 064ecd449e 17e959407c
commit eb7ff43f95
13 changed files with 1125 additions and 104 deletions
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76
src/compiler/checker.ts
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@@ -12467,22 +12467,7 @@ namespace ts {
callback(getTypeAtPosition(source, i), getTypeAtPosition(target, i));
}
if (targetRestTypeVariable) {
const sourceRestTypeVariable = getRestTypeParameter(source);
if (sourceRestTypeVariable && paramCount === sourceCount - 1) {
callback(sourceRestTypeVariable, targetRestTypeVariable);
}
else {
const types = [];
const names = [];
for (let i = paramCount; i < maxCount; i++) {
types.push(getTypeAtPosition(source, i));
names.push(getParameterNameAtPosition(source, i));
}
const minArgumentCount = getMinArgumentCount(source);
const minLength = minArgumentCount < paramCount ? 0 : minArgumentCount - paramCount;
const rest = createTupleType(types, minLength, sourceHasRest, names);
callback(rest, targetRestTypeVariable);
}
callback(getRestTypeAtPosition(source, paramCount), targetRestTypeVariable);
}
}
@@ -15284,43 +15269,35 @@ namespace ts {
}
const iife = getImmediatelyInvokedFunctionExpression(func);
if (iife && iife.arguments) {
const args = getEffectiveCallArguments(iife)!;
const indexOfParameter = func.parameters.indexOf(parameter);
if (parameter.dotDotDotToken) {
const restTypes: Type[] = [];
for (let i = indexOfParameter; i < iife.arguments.length; i++) {
restTypes.push(getWidenedLiteralType(checkExpression(iife.arguments[i])));
}
return restTypes.length ? createArrayType(getUnionType(restTypes)) : undefined;
return getSpreadArgumentType(iife, args, indexOfParameter, args.length, anyType, /*context*/ undefined);
}
const links = getNodeLinks(iife);
const cached = links.resolvedSignature;
links.resolvedSignature = anySignature;
const type = indexOfParameter < iife.arguments.length ?
getWidenedLiteralType(checkExpression(iife.arguments[indexOfParameter])) :
const type = indexOfParameter < args.length ?
getWidenedLiteralType(checkExpression(args[indexOfParameter])) :
parameter.initializer ? undefined : undefinedWideningType;
links.resolvedSignature = cached;
return type;
}
const contextualSignature = getContextualSignature(func);
if (contextualSignature) {
const funcHasRestParameters = hasRestParameter(func);
const len = func.parameters.length - (funcHasRestParameters ? 1 : 0);
const funcHasRestParameter = hasRestParameter(func);
const len = func.parameters.length - (funcHasRestParameter ? 1 : 0);
let indexOfParameter = func.parameters.indexOf(parameter);
if (getThisParameter(func) !== undefined && !contextualSignature.thisParameter) {
Debug.assert(indexOfParameter !== 0); // Otherwise we should not have called `getContextuallyTypedParameterType`.
indexOfParameter -= 1;
}
if (indexOfParameter < len) {
return getTypeAtPosition(contextualSignature, indexOfParameter);
}
// If last parameter is contextually rest parameter get its type
if (funcHasRestParameters &&
indexOfParameter === func.parameters.length - 1 &&
hasEffectiveRestParameter(contextualSignature) &&
func.parameters.length >= contextualSignature.parameters.length) {
return getTypeOfRestParameter(contextualSignature);
if (funcHasRestParameter && indexOfParameter === len) {
return getRestTypeAtPosition(contextualSignature, indexOfParameter);
}
}
}
@@ -17895,7 +17872,7 @@ namespace ts {
}
}
function isSpreadArgument(arg: Expression | undefined) {
function isSpreadArgument(arg: Expression | undefined): arg is Expression {
return !!arg && (arg.kind === SyntaxKind.SpreadElement || arg.kind === SyntaxKind.SyntheticExpression && (<SyntheticExpression>arg).isSpread);
}
@@ -18117,12 +18094,14 @@ namespace ts {
}
function getSpreadArgumentType(node: CallLikeExpression, args: ReadonlyArray<Expression>, index: number, argCount: number, restType: TypeParameter, context: InferenceContext | undefined) {
if (index === argCount - 1) {
const arg = getEffectiveArgument(node, args, index);
if (index >= argCount - 1) {
const arg = getEffectiveArgument(node, args, argCount - 1);
if (isSpreadArgument(arg)) {
// We are inferring from a spread expression in the last argument position, i.e. both the parameter
// and the argument are ...x forms.
return checkExpressionWithContextualType((<SpreadElement>arg).expression, restType, context);
return arg.kind === SyntaxKind.SyntheticExpression ?
createArrayType((<SyntheticExpression>arg).type) :
checkExpressionWithContextualType((<SpreadElement>arg).expression, restType, context);
}
}
const contextualType = getIndexTypeOfType(restType, IndexKind.Number) || anyType;
@@ -19651,6 +19630,27 @@ namespace ts {
return anyType;
}
function getRestTypeAtPosition(source: Signature, pos: number): Type {
const paramCount = getParameterCount(source);
const hasRest = hasEffectiveRestParameter(source);
if (hasRest && pos === paramCount - 1) {
const restTypeVariable = getRestTypeParameter(source);
if (restTypeVariable) {
return restTypeVariable;
}
}
const start = hasRest ? Math.min(pos, paramCount - 1) : pos;
const types = [];
const names = [];
for (let i = start; i < paramCount; i++) {
types.push(getTypeAtPosition(source, i));
names.push(getParameterNameAtPosition(source, i));
}
const minArgumentCount = getMinArgumentCount(source);
const minLength = minArgumentCount < start ? 0 : minArgumentCount - start;
return createTupleType(types, minLength, hasRest, names);
}
function getTypeOfRestParameter(signature: Signature) {
if (signature.hasRestParameter) {
const restType = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]);
@@ -19744,11 +19744,11 @@ namespace ts {
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType);
}
}
if (signature.hasRestParameter && context.hasRestParameter && signature.parameters.length >= context.parameters.length) {
if (signature.hasRestParameter) {
// parameter might be a transient symbol generated by use of `arguments` in the function body.
const parameter = last(signature.parameters);
if (isTransientSymbol(parameter) || !getEffectiveTypeAnnotationNode(<ParameterDeclaration>parameter.valueDeclaration)) {
const contextualParameterType = getTypeOfSymbol(last(context.parameters));
const contextualParameterType = getRestTypeAtPosition(context, len);
assignTypeToParameterAndFixTypeParameters(parameter, contextualParameterType);
}
}