STR: 1. open devtools debugger tab (check "Show Original Sources" option) 2. open http://people.mozilla.org/~ydelendik/tmp/dbgwast/t.html 3. select "labels.wast" source code 4. set breakpoint at line 12 5. refresh Actual result: Debugger stops but it does not show where is stops, no locals are visible Expected result: Debugger stops and let code to be stepped

It looks like the breakpoint you're setting is in top-level code that is executed immediately on refresh. This is a difficult problem. We need to load the source map before we set any breakpoints, or the breakpoints won't end up where you expect. We need to set the breakpoints before the script starts executing, or control will have already passed through the point where the breakpoint was supposed to be set. However, we also don't really want to wait for the source map to be loaded before the script starts executing, since that will hang the UI. I'd like for this to be fixed, but fixing it properly will require us to rethink some parts of the design of the debugger. That makes this a medium term project, so I'm going to flag this as P2.

This seems to work for me now. Yury, would you mind giving it a try as well?

Seems to work for me. However the __locals object is empty and I'm not sure if that's correct.

The test case at people.mozilla.org is lost, I'm unable to confirm the fix. Closing based on comment 2 and comment 3.