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Unable to set breakpoints in global lambda #34742

DanTup opened this Issue Oct 10, 2018 · 0 comments


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DanTup commented Oct 10, 2018

(Raised at Dart-Code/Dart-Code#1249 by @kentcb)

Given this code:

import 'package:test/test.dart';

typedef void VoidCallback();

void main() {
  final workingCase = SomeClass(() {
    // set a breakpoint on the following line and it will be hit

  test("breakpoint works", () {

  test("breakpoint does not work", () {

class SomeClass {
  final VoidCallback execute;


final nonWorkingCase = SomeClass(() {
  // set a breakpoint on the following line and it will not be hit

If you put breakpoints on the two marked locations, the second one gets rejected:

"details":"addBreakpointWithScriptUri: Cannot add breakpoint at line '28'"

If you run the file with dart --observe --pause-isolates-on-start .\test\broken_test.dart and then open in Observatory, the second breakpoint (the one that is missed) does not appear as a valid location to add a breakpoint:


As far as I can see, the only difference between the code is that one is inside the main method and the other is not.

@DanTup DanTup changed the title from Missed breakpoints in global lambda to Unable to set breakpoints in global lambda Oct 10, 2018

@mit-mit mit-mit added the area-vm label Oct 10, 2018

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