maxmustermann/TypeScript
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

Perform indexed access type transformations consistently

Browse source
This commit is contained in:
Anders Hejlsberg 2017-08-25 08:49:34 -07:00
parent 616bb5fcf6
commit 3d3ed04b28
1 changed files with 8 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
src/compiler/checker.ts
View file

@ -5906,6 +5906,10 @@ namespace ts {
}
function getConstraintOfIndexedAccess(type: IndexedAccessType) {
const transformed = getTransformedIndexedAccessType(type);
if (transformed) {
return transformed;
}
const baseObjectType = getBaseConstraintOfType(type.objectType);
const baseIndexType = getBaseConstraintOfType(type.indexType);
return baseObjectType || baseIndexType ? getIndexedAccessType(baseObjectType || type.objectType, baseIndexType || type.indexType) : undefined;
@ -7617,8 +7621,8 @@ namespace ts {
return false;
}
// Transform an indexed access occurring in a read position to a simpler form. Return the simpler form,
// or undefined if no transformation is possible.
// Transform an indexed access to a simpler form, if possible. Return the simpler form, or return
// undefined if no transformation is possible.
function getTransformedIndexedAccessType(type: IndexedAccessType): Type {
const objectType = type.objectType;
// Given an indexed access type T[K], if T is an intersection containing one or more generic types and one or
@ -9279,7 +9283,7 @@ namespace ts {
else if (target.flags & TypeFlags.IndexedAccess) {
// A type S is related to a type T[K] if S is related to A[K], where K is string-like and
// A is the apparent type of S.
const constraint = getConstraintOfType(<IndexedAccessType>target);
const constraint = getConstraintOfIndexedAccess(<IndexedAccessType>target);
if (constraint) {
if (result = isRelatedTo(source, constraint, reportErrors)) {
errorInfo = saveErrorInfo;
@ -9319,7 +9323,7 @@ namespace ts {
else if (source.flags & TypeFlags.IndexedAccess) {
// A type S[K] is related to a type T if A[K] is related to T, where K is string-like and
// A is the apparent type of S.
const constraint = getTransformedIndexedAccessType(<IndexedAccessType>source) || getConstraintOfIndexedAccess(<IndexedAccessType>source);
const constraint = getConstraintOfIndexedAccess(<IndexedAccessType>source);
if (constraint) {
if (result = isRelatedTo(constraint, target, reportErrors)) {
errorInfo = saveErrorInfo;