[Bug]: Error messages inside CATCH handling not [always] displayed

[steinhh]

Current Behavior

Inconsistently, errors happening inside CATCH error handling will not be displayed (even though CATCH,/cancel has been issued)

Expected Behavior

Errors should be reported correctly even after a CATCH has triggered

GitHub Repo

No response

Steps to Reproduce

1. Compile and run the following program with the debugger:

PRO test_crash
  catch, err
  IF err NE 0 THEN BEGIN
    catch, /cancel
    print, "Error in test_crash: " + err.tostring()
    help, /not_a_keyword
  END
  a = b
END

2. The output is (inconsistently):

.compile -v '/mn/sertan/u1/steinhh/sf/idl/test_spice_fits.pro'
% Compiled module: TEST_CRASH.

> test_crash
Error in test_crash: -181

> test_crash
Error in test_crash: -181

> test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          6
   /mn/sertan/u1/steinhh/sf/idl/test_spice_fits.pro
%                      TEST_CRASH          6
   /mn/sertan/u1/steinhh/sf/idl/test_spice_fits.pro
%                      TEST_CRASH          6
   /mn/sertan/u1/steinhh/sf/idl/test_spice_fits.pro
%                      $MAIN$          

> test_crash
Error in test_crash: -181

... etc

Failure Logs

?from where?

Operating System

• macOS (Intel x86_64)
• macOS (ARM64)
• Linux
• Windows

IDL Version

9.2.0

Additional Information

No response

[znorman-harris]

Thanks for reporting this! I'm wondering if this might be an IDL issue (as, on Windows, it works every time I run the file.

Let me ping one of our IDL dev's and see what they have to say.

For a little context, here's the output I see on Windows with IDL 9.2 which is always the same:

.compile -v 'D:\tes.pro'
% Compiled module: TEST_CRASH.

test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          9 D:\tes.pro

%                      $MAIN$          
test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          9 D:\tes.pro
%                      TEST_CRASH          9 D:\tes.pro
%                      $MAIN$          
test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          9 D:\tes.pro
2
%                      TEST_CRASH          9 D:\tes.pro
%                      $MAIN$          
test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          9 D:\tes.pro
3
%                      TEST_CRASH          9 D:\tes.pro
%                      $MAIN$          
test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          9 D:\tes.pro
4
%                      TEST_CRASH          9 D:\tes.pro
%                      $MAIN$          
test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          9 D:\tes.pro
5
%                      TEST_CRASH          9 D:\tes.pro
%                      $MAIN$          

[steinhh]

But your "Execution halted at" stack dump doesn't grow like mine does?

[steinhh]

BTW the idl history file (.idl/vscode/idl-history.idllog) reflects the output above - sometimes a crash report, sometimes not. So yes it's plausible that it's an IDL issue:

idl input .compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'
  % Compiled module: TEST_CRASH.


idl input test_crash
  Error in test_crash: -181
  % Keyword NOT_A_KEYWORD not allowed in call to: HELP
  % Execution halted at: TEST_CRASH          6
     /Users/steinhh/solo-spice-ql/tests/test_crash.pro
  %                      $MAIN$


idl input .compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'
  % Compiled module: TEST_CRASH.

idl input test_crash
  Error in test_crash: -181

idl input .compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'
  % Compiled module: TEST_CRASH.

idl input test_crash
  Error in test_crash: -181
  % Keyword NOT_A_KEYWORD not allowed in call to: HELP
  % Execution halted at: TEST_CRASH          6
     /Users/steinhh/solo-spice-ql/tests/test_crash.pro
  %                      $MAIN$

[steinhh]

Here's the extension log corresponding to first one execution with a correct error message, then another one without the error message:

idl-debug-adapter info IDL session history file: /Users/steinhh/.idl/vscode/idl-history.idllog
idl-session info Starting IDL
  {
    cmd: '/usr/local/bin/idl',
    dir: '/Applications/NV5/idl',
    path: '+/Users/steinhh/.vscode/extensions/idl.idl-for-vscode-5.0.1/idl/vscode:+/Users/steinhh/solo-spice-ql:+/Users/steinhh/ssw/gen:+/Users/steinhh/ssw/iris:+/Users/steinhh/ssw/so:+/Users/steinhh/ssw/sdo:+/Users/steinhh/ssw/vobs:<IDL_DEFAULT>',
    dlm_path: '<IDL_DEFAULT>:/Users/steinhh/ssw/site/dlm/darwin.arm64:+/usr/local/bin'
  }
idl-debug-adapter debug Configuration done request
idl-session info IDL has started!
idl-debug-adapter debug Evaluate
  {
    command: 'vscode_getIDLInfo',
    splitCommands: [ 'vscode_getIDLInfo' ],
    useSplit: [ 'vscode_getIDLInfo' ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: false,
      silent: true,
      idlInfo: false,
      newLine: false,
      noWait: true,
      errorCheck: false
    }
  }
idl-session debug Executing via stdio:
  { command: 'vscode_getIDLInfo' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"arch":"arm64","os":"darwin","os_family":"unix","os_name":"Mac OS X","release":"9.2.0","build_date":"Jul 21 2025 (481746)","memory_bits":64,"file_offset_bits":64,"dir":"//Applications/NV5/idl92"}'
    }
  }
idl-tree-click-handler debug Clicked on button "View Extension Logs"
idl-lsp info Running change detection with 988 global(s) updated after type detection
idl-lsp info Finished change detection after updating 1060 global(s) with 3 step(s) over 2680 ms, exit conditions:
  { noChanges: false, maxIter: false, sameGlobals: true }
idl-lsp info Finished indexing 5681 file(s) in 24659 ms, see below for additional information
  {
    lines: 973934,
    app_platform: 'darwin',
    app_arch: 'arm64',
    app_cpus: 12,
    app_ram: 64,
    app_ram_used: 4.25,
    num_workers: 6,
    parse_time: 24.46,
    parse_rate: 39817,
    num_pro: 5670,
    num_pro_def: 0,
    num_save: 11,
    num_idl_task: 0,
    num_envi_task: 0,
    num_idl_json: 0,
    num_notebook: 0,
    time_total_ms: 24659,
    time_search_ms: 7,
    time_config_ms: 0,
    time_task_ms: 0,
    time_save_ms: 0,
    time_notebook_ms: 0,
    time_pro_ms: 24460
  }
idl-lsp debug Document symbol request
  {
    textDocument: { uri: 'file:///Users/steinhh/solo-spice-ql/tests/test_crash.pro' }
  }
idl-lsp debug Semantic tokens request
  {
    textDocument: { uri: 'file:///Users/steinhh/solo-spice-ql/tests/test_crash.pro' }
  }
idl-lsp debug Document symbol request
  {
    textDocument: { uri: 'file:///Users/steinhh/solo-spice-ql/tests/test_crash.pro' }
  }
idl-lsp debug Hover help request
  {
    textDocument: { uri: 'file:///Users/steinhh/solo-spice-ql/tests/test_crash.pro' },
    position: { line: 3, character: 16 }
  }
idl-lsp debug Hover help request
  {
    textDocument: { uri: 'file:///Users/steinhh/solo-spice-ql/tests/test_crash.pro' },
    position: { line: 4, character: 34 }
  }
idl-command info Running file
idl-debug-adapter debug Evaluate
  {
    command: ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'",
    splitCommands: [ ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'" ],
    useSplit: [ ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'" ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: true,
      silent: false,
      idlInfo: true,
      newLine: true,
      noWait: false,
      errorCheck: true
    }
  }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"$main$","file":"","line":0}],"variables":[{"name":"chkcon","type":"string","description":"string"},{"name":"count","type":"long","description":0},{"name":"cwd","type":"string","description":"string"},{"name":"exec_after_reset","type":"string","description":"string"},{"name":"home","type":"string","description":"string"},{"name":"i","type":"int","description":1},{"name":"idl_startup","type":"string","description":"string"},{"name":"inst","type":"string","description":"string"},{"name":"iss","type":"int","description":0},{"name":"isspartan","type":"byte","description":0},{"name":"isy","type":"int","description":0},{"name":"newgen","type":"string","description":"string"},{"name":"newssw","type":"string","description":"string"},{"name":"qtemp","type":"long","description":0},{"name":"reset_done","type":"byte","description":0},{"name":"soho","type":"string","description":"string"},{"name":"ssw_startup","type":"byte","description":0},{"name":"ssw_startup_delete","type":"byte","description":0},{"name":"test_compile_dir","type":"string","description":"string"},{"name":"use_steinhh_paths","type":"byte","description":1},{"name":"valid","type":"long","description":-1},{"name":"wdc","type":"string","description":"string"},{"name":"x","type":"long","description":0},{"name":"yohkoh","type":"string","description":"string"},{"name":"zdbase","type":"string","description":"string"},{"name":"zdbase_eis","type":"string","description":"string"},{"name":"zdbase_user","type":"string","description":"string"}],"envi":false}'
    }
  }
idl-session debug Executing via stdio:
  {
    command: ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'"
  }
idl-session debug Error check output
idl-session debug Output:
  { res: { idlOutput: '% Compiled module: TEST_CRASH.' } }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"$main$","file":"","line":0}],"variables":[{"name":"chkcon","type":"string","description":"string"},{"name":"count","type":"long","description":0},{"name":"cwd","type":"string","description":"string"},{"name":"exec_after_reset","type":"string","description":"string"},{"name":"home","type":"string","description":"string"},{"name":"i","type":"int","description":1},{"name":"idl_startup","type":"string","description":"string"},{"name":"inst","type":"string","description":"string"},{"name":"iss","type":"int","description":0},{"name":"isspartan","type":"byte","description":0},{"name":"isy","type":"int","description":0},{"name":"newgen","type":"string","description":"string"},{"name":"newssw","type":"string","description":"string"},{"name":"qtemp","type":"long","description":0},{"name":"reset_done","type":"byte","description":0},{"name":"soho","type":"string","description":"string"},{"name":"ssw_startup","type":"byte","description":0},{"name":"ssw_startup_delete","type":"byte","description":0},{"name":"test_compile_dir","type":"string","description":"string"},{"name":"use_steinhh_paths","type":"byte","description":1},{"name":"valid","type":"long","description":-1},{"name":"wdc","type":"string","description":"string"},{"name":"x","type":"long","description":0},{"name":"yohkoh","type":"string","description":"string"},{"name":"zdbase","type":"string","description":"string"},{"name":"zdbase_eis","type":"string","description":"string"},{"name":"zdbase_user","type":"string","description":"string"}],"envi":false}'
    }
  }
idl-debug-adapter debug Evaluate
  {
    command: 'help, /breakpoints',
    splitCommands: [ 'help, /breakpoints' ],
    useSplit: [ 'help, /breakpoints' ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: false,
      silent: true,
      idlInfo: false,
      newLine: false,
      noWait: false,
      errorCheck: false
    }
  }
idl-session debug Executing via stdio:
  { command: 'help, /breakpoints' }
idl-session debug Error check output
idl-session debug Output:
  { res: { idlOutput: '' } }
idl-debug-adapter debug Evaluate
  {
    command: 'test_crash',
    splitCommands: [ 'test_crash' ],
    useSplit: [ 'test_crash' ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: true,
      silent: false,
      idlInfo: true,
      newLine: true,
      noWait: false,
      errorCheck: true
    }
  }
idl-session debug Executing via stdio:
  { command: 'test_crash' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: 'Error in test_crash: -181\n' +
        '% Keyword NOT_A_KEYWORD not allowed in call to: HELP\n' +
        '% Execution halted at: TEST_CRASH          6\n' +
        '   /Users/steinhh/solo-spice-ql/tests/test_crash.pro\n' +
        '%                      $MAIN$          ',
      stopped: {
        reason: 'error',
        stack: {
          file: '/Users/steinhh/solo-spice-ql/tests/test_crash.pro%                      $MAIN$          ',
          line: 6,
          index: 0,
          name: 'TEST_CRASH'
        }
      }
    }
  }
idl-debug-adapter debug Stopped because "error" and can send "true"
  {
    file: '/Users/steinhh/solo-spice-ql/tests/test_crash.pro%                      $MAIN$          ',
    line: 6,
    index: 0,
    name: 'TEST_CRASH'
  }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}'
    }
  }
idl-debug-adapter debug Stack trace request
  { threadId: 1, startFrame: 0, levels: 20 }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}'
    }
  }
idl-debug-adapter debug Call stack
  [
    StackFrame {
      id: 0,
      source: Source {
        name: 'test_crash.pro',
        path: '/Users/steinhh/solo-spice-ql/tests/test_crash.pro',
        sourceReference: 0
      },
      line: 6,
      column: 0,
      name: 'test_crash'
    }
  ]
idl-command info Running file
idl-debug-adapter debug Evaluate
  {
    command: ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'",
    splitCommands: [ ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'" ],
    useSplit: [ ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'" ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: true,
      silent: false,
      idlInfo: true,
      newLine: true,
      noWait: false,
      errorCheck: true
    }
  }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}'
    }
  }
idl-session debug Executing via stdio:
  { command: 'retall' }
idl-session debug Error check output
idl-session debug Output:
  { res: { idlOutput: '' } }
idl-session debug Executing via stdio:
  {
    command: ".compile -v '/Users/steinhh/solo-spice-ql/tests/test_crash.pro'"
  }
idl-session debug Error check output
idl-session debug Output:
  { res: { idlOutput: '% Compiled module: TEST_CRASH.' } }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"$main$","file":"","line":0}],"variables":[{"name":"chkcon","type":"string","description":"string"},{"name":"count","type":"long","description":0},{"name":"cwd","type":"string","description":"string"},{"name":"exec_after_reset","type":"string","description":"string"},{"name":"home","type":"string","description":"string"},{"name":"i","type":"int","description":1},{"name":"idl_startup","type":"string","description":"string"},{"name":"inst","type":"string","description":"string"},{"name":"iss","type":"int","description":0},{"name":"isspartan","type":"byte","description":0},{"name":"isy","type":"int","description":0},{"name":"newgen","type":"string","description":"string"},{"name":"newssw","type":"string","description":"string"},{"name":"qtemp","type":"long","description":0},{"name":"reset_done","type":"byte","description":0},{"name":"soho","type":"string","description":"string"},{"name":"ssw_startup","type":"byte","description":0},{"name":"ssw_startup_delete","type":"byte","description":0},{"name":"test_compile_dir","type":"string","description":"string"},{"name":"use_steinhh_paths","type":"byte","description":1},{"name":"valid","type":"long","description":-1},{"name":"wdc","type":"string","description":"string"},{"name":"x","type":"long","description":0},{"name":"yohkoh","type":"string","description":"string"},{"name":"zdbase","type":"string","description":"string"},{"name":"zdbase_eis","type":"string","description":"string"},{"name":"zdbase_user","type":"string","description":"string"}],"envi":false}'
    }
  }
idl-debug-adapter debug Evaluate
  {
    command: 'help, /breakpoints',
    splitCommands: [ 'help, /breakpoints' ],
    useSplit: [ 'help, /breakpoints' ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: false,
      silent: true,
      idlInfo: false,
      newLine: false,
      noWait: false,
      errorCheck: false
    }
  }
idl-session debug Executing via stdio:
  { command: 'help, /breakpoints' }
idl-session debug Error check output
idl-session debug Output:
  { res: { idlOutput: '' } }
idl-debug-adapter debug Evaluate
  {
    command: 'test_crash',
    splitCommands: [ 'test_crash' ],
    useSplit: [ 'test_crash' ],
    reset: false,
    close: false,
    options: {
      continued: false,
      echo: true,
      silent: false,
      idlInfo: true,
      newLine: true,
      noWait: false,
      errorCheck: true
    }
  }
idl-session debug Executing via stdio:
  { command: 'test_crash' }
idl-session debug Error check output
idl-session debug Output:
  { res: { idlOutput: 'Error in test_crash: -181' } }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '% Keyword NOT_A_KEYWORD not allowed in call to: HELP\n' +
        '% Execution halted at: TEST_CRASH          6\n' +
        '   /Users/steinhh/solo-spice-ql/tests/test_crash.pro\n' +
        '%                      $MAIN$          \n' +
        '{"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}',
      stopped: {
        reason: 'error',
        stack: {
          file: '/Users/steinhh/solo-spice-ql/tests/test_crash.pro%                      $MAIN$          {"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}',
          line: 6,
          index: 0,
          name: 'TEST_CRASH'
        }
      }
    }
  }
idl-debug-adapter debug Stopped because "error" and can send "true"
  {
    file: '/Users/steinhh/solo-spice-ql/tests/test_crash.pro%                      $MAIN$          {"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}',
    line: 6,
    index: 0,
    name: 'TEST_CRASH'
  }
idl-debug-adapter debug Stack trace request
  { threadId: 1, startFrame: 0, levels: 20 }
idl-session debug Executing via stdio:
  { command: '  vscode_getScopeInfo, -0' }
idl-session debug Error check output
idl-session debug Output:
  {
    res: {
      idlOutput: '{"scope":[{"routine":"test_crash","file":"/Users/steinhh/solo-spice-ql/tests/test_crash.pro","line":6},{"routine":"$main$","file":"","line":0}],"variables":[{"name":"a","type":"undefined","description":"undefined"},{"name":"b","type":"undefined","description":"undefined"},{"name":"err","type":"long","description":-181}],"envi":false}'
    }
  }
idl-debug-adapter debug Call stack
  [
    StackFrame {
      id: 0,
      source: Source {
        name: 'test_crash.pro',
        path: '/Users/steinhh/solo-spice-ql/tests/test_crash.pro',
        sourceReference: 0
      },
      line: 6,
      column: 0,
      name: 'test_crash'
    }
  ]
idl-debug-adapter debug Scopes request
  { frameId: 0 }
idl-debug-adapter debug Variables request
  { frameId: 0 }
idl-lsp debug Hover help request
  {
    textDocument: { uri: 'file:///Users/steinhh/solo-spice-ql/tests/test_crash.pro' },
    position: { line: 6, character: 2 }
  }

[chris-torrence]

But your "Execution halted at" stack dump doesn't grow like mine does?

I wonder if this is a weird timing issue between the output from the IDL_Machine (the IDL process) and VS Code, where it doesn't always receive the messages in time (or in the correct order).

This isn't a bug in core IDL. If I run this at the command line (not within VS Code), or in the IDL Workbench, then the stack dump does grow as expected:

IDL> test_crash 
% Compiled module: TEST_CRASH.
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          6 C:\Users\chris.torrence\IDLWorkspace\Default\test_crash.pro
%                      $MAIN$
IDL> test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          6 C:\Users\chris.torrence\IDLWorkspace\Default\test_crash.pro
%                      TEST_CRASH          6 C:\Users\chris.torrence\IDLWorkspace\Default\test_crash.pro
%                      $MAIN$
IDL> test_crash
Error in test_crash: -181
% Keyword NOT_A_KEYWORD not allowed in call to: HELP
% Execution halted at: TEST_CRASH          6 C:\Users\chris.torrence\IDLWorkspace\Default\test_crash.pro
%                      TEST_CRASH          6 C:\Users\chris.torrence\IDLWorkspace\Default\test_crash.pro
%                      TEST_CRASH          6 C:\Users\chris.torrence\IDLWorkspace\Default\test_crash.pro
%                      $MAIN$

So IDL itself is behaving as expected. It's just something strange between the IDL output and the VS Code console?

[steinhh]

Hmm... using IDL on the command line both on my Mac (ARM64) and on Linux I always get the right results (error message + stack dump), should've tried that right away :)