Skip to content

loosen number index check, fixes #15768 #17767

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 14, 2017
Merged

loosen number index check, fixes #15768 #17767

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1d6863a
loosen number index check, fixes #15768
KiaraGrouwstra Aug 13, 2017
4268e13
simplify fix as suggested by @ahejlsberg
KiaraGrouwstra Aug 14, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 6 additions & 7 deletions src/compiler/checker.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18758,13 +18758,12 @@ namespace ts {
if (isTypeAssignableTo(indexType, getIndexType(objectType))) {
return type;
}
// Check if we're indexing with a numeric type and the object type is a generic
// type with a constraint that has a numeric index signature.
if (maybeTypeOfKind(objectType, TypeFlags.TypeVariable) && isTypeAssignableToKind(indexType, TypeFlags.NumberLike)) {
const constraint = getBaseConstraintOfType(objectType);
if (constraint && getIndexInfoOfType(constraint, IndexKind.Number)) {
return type;
}
// Check if we're indexing with a numeric type and if either object or index types
// is a generic type with a constraint that has a numeric index signature.
const typeOrConstraint = (tp: Type) => maybeTypeOfKind(tp, TypeFlags.TypeVariable) ? getBaseConstraintOfType(tp) || tp : tp;
if (isTypeAssignableToKind(typeOrConstraint(indexType), TypeFlags.NumberLike) &&
getIndexInfoOfType(typeOrConstraint(objectType), IndexKind.Number)) {
return type;
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Change this to just:

if (getIndexInfoOfType(getApparentType(objectType), IndexKind.Number) && isTypeAssignableToKind(indexType, TypeFlags.NumberLike)) {
    return type;
}

Otherwise PR looks good. Thanks!

}
error(accessNode, Diagnostics.Type_0_cannot_be_used_to_index_type_1, typeToString(indexType), typeToString(objectType));
return type;
Expand Down
5 changes: 5 additions & 0 deletions tests/baselines/reference/genericNumberIndex.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
//// [genericNumberIndex.ts]
type X<I extends number> = ['a'][I];


//// [genericNumberIndex.js]
6 changes: 6 additions & 0 deletions tests/baselines/reference/genericNumberIndex.symbols
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
=== tests/cases/compiler/genericNumberIndex.ts ===
type X<I extends number> = ['a'][I];
>X : Symbol(X, Decl(genericNumberIndex.ts, 0, 0))
>I : Symbol(I, Decl(genericNumberIndex.ts, 0, 7))
>I : Symbol(I, Decl(genericNumberIndex.ts, 0, 7))

6 changes: 6 additions & 0 deletions tests/baselines/reference/genericNumberIndex.types
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
=== tests/cases/compiler/genericNumberIndex.ts ===
type X<I extends number> = ['a'][I];
>X : ["a"][I]
>I : I
>I : I

1 change: 1 addition & 0 deletions tests/cases/compiler/genericNumberIndex.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
type X<I extends number> = ['a'][I];