Scenario: As a user, I want typescript compiler to default-exclude output transpiled files to compilerOptions.outDir with compilerOptions.declaration property set to true. I would expect that outDir is excluded by default, because:

• it would prevent me from importing definitions from outDir by error, which is easy to do with intellisense
• it would prevent me from having TS5055 errors such as spotted in TypeScript complains about overwriting .d.ts files that are potentially known outputs #16749 and tsc generating TS5055 error when generating declaration files #6046
• tsc CLI has already implemented this behaviour, see PR exclude outDir and add more default excludes #8703