typesVersions should not be affected by "types": ""

[ghost]

TypeScript Version: 3.2.0-dev.20181101

Code

(This is just typesVersions.justIndex.ts plus "types": "",)

// @baseUrl: /
// @traceResolution: true
// @target: esnext
// @module: commonjs

// @filename: /a/package.json
{
    "types": "",
    "typesVersions": {
        ">=3.1.0-0": { "*" : ["ts3.1/*"] }
    }
}

// @filename: /a/ts3.1/index.d.ts
export const a = 0;

// @filename: /b/user.ts
import { a } from "a";

Expected behavior:

No error.

Actual behavior:

Module resolution fails. The trace indicates that it is now looking for a file named "*.d.ts" instead of parsing the pattern correctly.

[rbuckton]

According to the documentation for Node's module resolution:

LOAD_AS_DIRECTORY(X)
1. If X/package.json is a file,
   a. Parse X/package.json, and look for "main" field.
   b. If "main" is a falsy value, GOTO 2.
   c. let M = X + (json main field)
   d. LOAD_AS_FILE(M)
   e. LOAD_INDEX(M)
   f. LOAD_INDEX(X) DEPRECATED
   g. THROW "not found"
2. LOAD_INDEX(X)

Step 1.b. indicates we should ignore a "falsy" value for "main", and we should probably do the same for "types", however in both cases we only check for undefined and allow "".