Correctly check computed property names in type-space get/set accessors #47156
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Fixes #47146 (introduced by #42425 which enabled this syntax)
Previously this code ran without error:
because we incorrectly swallowed the errors in
checkComputedPropertyNameunder the assumption that we were looking at a{ [K in T]: U }declaration. The code path where the error would have been detected -- in the mapped checking logic -- obviously does not run because this is not actually a mapped type.Thankfully the computed type was completely useless (see comments in linked issue), so it isn't feasible that anyone took a dependency on this.