problem with referencing external modules in 1.6.0-dev.20150818

[zpdDG4gta8XKpMCd]

a.ts

export var c = '';

b.ts

import a = require('./a');

tsconfig.json

{
    "files": [
        "./a.ts",
        "./b.ts"
    ]
}

node ./node_modules/typescript/lib/tsc.js --outDir ./commonjs --module commonjs --target es5 --declaration --noResolve --noEmitOnError --noImplicitAny

gives:

b.ts(1,20): error TS2307: Cannot find module './a'.