API: crash while printing ImportClause with removeComments: true

[ajafff]

TypeScript Version: 2.7.2, 2.8.0-dev.20180228

Search Terms:

Code

import * as ts from 'typescript';
const sourceFile = ts.createSourceFile('import-foo.ts', "import {foo} from 'foo';", ts.ScriptTarget.ESNext);
ts.createPrinter().printFile(sourceFile); // works as expected
ts.createPrinter({removeComments: true}).printFile(sourceFile); // throws

Expected behavior:

No exception

Actual behavior:

This happens because ImportClause.name is undefined. Also note that ImportClause.namedBindings could also be undefined and there is no check for that.

TypeError: Cannot read property 'kind' of undefined
    at pipelineEmitUnspecified (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71850:29)
    at pipelineEmitWithHint (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71831:50)
    at pipelineEmitWithSourceMap (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71822:17)
    at emitNodeWithComments (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:69263:17)
    at pipelineEmitWithComments (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71811:17)
    at pipelineEmitWithNotification (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71805:17)
    at emit (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71792:13)
    at emitImportClause (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:73228:13)
    at pipelineEmitUnspecified (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:72034:28)
    at pipelineEmitWithHint (/home/klaus/code/wotan/node_modules/typescript/lib/typescript.js:71831:50)

Playground Link:

Related Issues:

[weswigham]

Looks like the issue is that emitNodeWithComments handles node being undefined (and stops proceeding down the pipeline if it is), but onEmitSourceMapOfNode and/or pipelineEmitWithHint do not (so if comment emit is off the pipeline continues and blows up 😄 ).