angular-cli: Incorrect line numbers in sourcemaps

OS?

Windows 10

Versions.

angular-cli: 1.0.0-beta.18
node: 6.5.0
os: win32 x64

Checked a beta.17 project, does not appear to occur there. Lines seem to be correct for debugging.

Repro steps.

• ng new source-map
• cd source-map
• ng serve
• Open src/app/app.component.ts and add some testing code

export class AppComponent {
  title = 'app works!';

  ngOnInit(){
    let value = true;
    if (value){
      value = false;
    }
  }
}

• Open devtools (tested in Chrome)
• ctrl+p and open app.component.ts
• Set breakpoint on line 12 (let value = true) and line 14 (value = false)
• Refresh page
• Hit breakpoint on line 12, notice call stack is outside ngOnInit even though breakpoint is within
• Hit breakpoint on line 14, notice call stack is within ngOnInit but value = undefined
• Step and see code execute as expected, but highlighted line to be shifted by a few lines

Other useful info

Seems to shift by ~ 5 lines in my local project, not sure if it is the same shift in the repro (repro shift looks like 3?). Shift can be seen in VS Code Chrome Debugging - where line numbers are given for the mappings.

Maps 48991 (actual line in main.bundle.js that breakpoint is set to in vscode) to 48986 (where the breakpoint actually is during runtime)