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Generic constraints cannot be applied to template literalsΒ #55493
Description
π Search Terms
Generic constraints
template literals
π Version & Regression Information
5.1.6
β― Playground Link
π» Code
type templateLiteralObject = Record< `${string}_${string}`,any> // or { [k : `${string}_${string}`]: any }
const test0 = {aaa:123} satisfies templateLiteralObject // error: Type '{ aaa: number; }' does not satisfy the expected type 'templateLiteral'.The error is as expected .
type foo<T extends templateLiteralObject> = T
type test1 = foo<{aaa:123}> // Hope this is an error. Because test0 will report an error
type test2 = {aaa:123} extends templateLiteralObject ? true : false // also should be false,Currently is trueπ Actual behavior
test0 throw errorοΌ Type '{ aaa: number; }' does not satisfy the expected type 'templateLiteral'.
but test1 No error reported
π Expected behavior
Hope test1 reported an error
Additional information about the issue
No response
Activity
fatcerberus commentedon Aug 24, 2023
test0is an excess property check error, not a type error. In general, objects can have extra properties, so you canβt constrain the set of allowed keys. See #55152.typescript-bot commentedon Aug 27, 2023
This issue has been marked as "Working as Intended" and has seen no recent activity. It has been automatically closed for house-keeping purposes.