TypeError: Cannot read property 'getLineCount' of null

[bpasero]

I just ran "out of sources" an extension to debug and hit a breakpoint when I saw this:

 ERR Cannot read property 'getLineCount' of null: TypeError: Cannot read property 'getLineCount' of null
    at DebugEditorContribution.getWordToPositionsMap (file:///Users/bpasero/Development/monaco/out/vs/workbench/parts/debug/electron-browser/debugEditorContribution.js:468:53)
    at DebugEditorContribution.createInlineValueDecorationsInsideRange (file:///Users/bpasero/Development/monaco/out/vs/workbench/parts/debug/electron-browser/debugEditorContribution.js:404:43)
    at file:///Users/bpasero/Development/monaco/out/vs/workbench/parts/debug/electron-browser/debugEditorContribution.js:386:30
    at Object.notifySuccess [as _notify] (file:///Users/bpasero/Development/monaco/out/vs/base/common/winjs.base.raw.js:1170:59)
    at Object.enter (file:///Users/bpasero/Development/monaco/out/vs/base/common/winjs.base.raw.js:852:30)
    at Promise_ctor._run (file:///Users/bpasero/Development/monaco/out/vs/base/common/winjs.base.raw.js:1068:29)
    at Promise_ctor._completed (file:///Users/bpasero/Development/monaco/out/vs/base/common/winjs.base.raw.js:1036:18)
    at file:///Users/bpasero/Development/monaco/out/vs/workbench/parts/debug/node/v8Protocol.js:34:25
    at RawDebugSession.V8Protocol.dispatch (file:///Users/bpasero/Development/monaco/out/vs/workbench/parts/debug/node/v8Protocol.js:111:29)
    at RawDebugSession.V8Protocol.handleData (file:///Users/bpasero/Development/monaco/out/vs/workbench/parts/debug/node/v8Protocol.js:79:34)