8000 Allow non-unit types in union discriminants by ahejlsberg · Pull Request #27695 · microsoft/TypeScript · GitHub
[go: up one dir, main page]
Skip to content

Allow non-unit types in union discriminants #27695

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 5 commits into from
Oct 15, 2018
Merged

Allow non-unit types in union discriminants #27695

Changes from 1 commit
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
d069875
Allow discriminant property to contain some non-unit types
ahejlsberg Oct 10, 2018
c110f57
Discriminant must include at least one unit type and no instantiable …
ahejlsberg Oct 10, 2018
7737cd5
Accept new baselines
ahejlsberg Oct 10, 2018
22907bf
Add tests
ahejlsberg Oct 10, 2018
6cdba6d
Accept new baselines
ahejlsberg Oct 10, 2018
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
Prev Previous commit
Next Next commit
Discriminant must include at least one unit type and no instantiable … 
…types
  • Loading branch information
@ahejlsberg
ahejlsberg committed Oct 10, 2018
commit c110f57deb0c423c4e160ab5bce74c35187cb039
20 changes: 15 additions & 5 deletions src/compiler/checker.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12919,10 +12919,6 @@ namespace ts {
isUnitType(type);
}

function maybeUnitType(type: Type): boolean {
return type.flags & TypeFlags.Union ? some((<UnionType>type).types, isUnitType) : isUnitType(type);
}

function getBaseTypeOfLiteralType(type: Type): Type {
return type.flags & TypeFlags.EnumLiteral ? getBaseTypeOfEnumLiteralType(<LiteralType>type) :
type.flags & TypeFlags.StringLiteral ? stringType :
Expand Down Expand Up @@ -14216,12 +14212,26 @@ namespace ts {
return undefined;
}

function isDiscriminantType(type: Type): boolean {
if (type.flags & TypeFlags.Union) {
if (type.flags & (TypeFlags.Boolean | TypeFlags.EnumLiteral)) {
return true;
}
let combined = 0;
for (const t of (<UnionType>type).types) combined |= t.flags;
if (combined & TypeFlags.Unit && !(combined & TypeFlags.Instantiable)) {
return true;
}
}
return false;
}

function isDiscriminantProperty(type: Type | undefined, name: __String) {
if (type && type.flags & TypeFlags.Union) {
const prop = getUnionOrIntersectionProperty(<UnionType>type, name);
if (prop && getCheckFlags(prop) & CheckFlags.SyntheticProperty) {
if ((<TransientSymbol>prop).isDiscriminantProperty === undefined) {
(<TransientSymbol>prop).isDiscriminantProperty = !!((<TransientSymbol>prop).checkFlags & CheckFlags.HasNonUniformType) && maybeUnitType(getTypeOfSymbol(prop));
(<TransientSymbol>prop).isDiscriminantProperty = !!((<TransientSymbol>prop).checkFlags & CheckFlags.HasNonUniformType) && isDiscriminantType(getTypeOfSymbol(prop));
}
return !!(<TransientSymbol>prop).isDiscriminantProperty;
}
Expand Down
0