TypeScript complains about overwriting .d.ts files that are potentially known outputs

Using tsc at the command line, I got

error TS5055: Cannot write file '/Users/alexamil/WebstormProjects/oresoftware/ldap-pool/index.d.ts' because it would overwrite input file.

why? :)

my tsconfig.json file is as follows

{
  "compilerOptions": {
    "declaration": true,
    "baseUrl": ".",
    "types": [
      "node"
    ],
    "typeRoots": [
      "node_modules/@types"
    ],
    "target": "es5",
    "module": "commonjs",
    "noImplicitAny": true,
    "removeComments": true,
    "allowUnreachableCode": true,
    "lib": [
      "es2015",
      "es2016",
      "es2017"
    ]
  },
  "compileOnSave": false,
  "exclude": [
    "node_modules"
  ]
}

Reproduce the report with the command-line tsc invocation and the provided tsconfig.json, focusing on declaration output and the excluded node_modules directory. Trace how the compiler identifies input files and generated .d.ts outputs, then determine the expected behavior for this case and add or update regression coverage if the behavior should change.