error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
error TS6054: File 'tests/cases/compiler/b.js.map' has an unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.


!!! error TS5055: Cannot write file 'tests/cases/compiler/b.js' because it would overwrite input file.
!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
!!! error TS6054: File 'tests/cases/compiler/b.js.map' has an unsupported extension. The only supported extensions are '.ts', '.tsx', '.d.ts', '.js', '.jsx'.
==== tests/cases/compiler/a.ts (0 errors) ====
    class c {
    }
    
==== tests/cases/compiler/b.js.map (0 errors) ====
    function foo() {
    }
    
==== tests/cases/compiler/b.js (0 errors) ====
    function bar() {
    }