As of Typescript 4.9, this is syntactically correct and also type-checks successfully (playground).
However in Deno 1.40.4 (with Typescript 5.3.3), the CLI instead fails with this diagnostic:
error: The module's source code could not be parsed: Expected ';', '}' or <eof> at file:///redacted/type_tests.ts:1:20
Array<5> satisfies unknown;
~~~~~~~
This appears to persist when an expression like this is used elsewhere (eg wrapped in parens, used on the RHS of an assignment, etc).
I imagine this is getting mis-parsed as the equivalent of (Array < 5 > satisfies) unknown; which would be invalid. That's just speculation however.
Version: Deno 1.40.4
Consider this one-line TS file:
As of Typescript 4.9, this is syntactically correct and also type-checks successfully (playground).
However in Deno 1.40.4 (with Typescript 5.3.3), the CLI instead fails with this diagnostic:
This appears to persist when an expression like this is used elsewhere (eg wrapped in parens, used on the RHS of an assignment, etc).
I imagine this is getting mis-parsed as the equivalent of
(Array < 5 > satisfies) unknown;
which would be invalid. That's just speculation however.❤️