Mirror of forum.nim-lang.org

13605 :: doAssert in a template: how to report the line at caller site

• hmf (orginal) [2025-12-31T16:09:07+01:00] view original

  I have the following code:

  
  const GL_DEBUG_CHECK=true
  
  template checkError() =
    if GL_DEBUG_CHECK==true:
      let (e, m) = checkErrorCode()
      doAssert(e == GL_NO_ERROR, $m)
  Run

  and in the application I have:

  
  ...
      glBindVertexArray( vao_polygon )
      glDrawArrays( GL_POLYGON, 0, polygon.len.cint )
      checkError()
  ...
  Run

  When an error does occur, doAssert reports the line at the checkError template and not at the call of this template in the main code.

  My question is: is it possible to have doAssert indicate the line at the call site?

  TIA

---

• elcritch (orginal) [2025-12-31T16:35:43+01:00] view original

  This annoys me this as well. Rarely do I care about the template triggering the issue. It changed sometime a while back in the 2.0 series I think. Essentially the templates set the lineDir directives now.

  @araq is there an option to change this behavior?

---

• Araq (orginal) [2025-12-31T17:15:47+01:00] view original

  There is a pragma for that:

  
  template assertImpl(cond: bool, msg: string, expr: string, enabled: static[bool]) =
    const
      loc = instantiationInfo(fullPaths = compileOption("excessiveStackTrace"))
    {.line: loc.}:
      if not cond:
        failedAssertImpl(msg)
  Run

---

• hmf (orginal) [2025-12-31T17:56:00+01:00] view original

  My apologies but I cannot understand the answer. I have tried the following:

  1. Add a {.excessiveStackTrace.} to the checkError (compilation fails, no such pragma)
  2. Added the line --excessiveStackTrace:on to my configs.nim (no changes)
  3. Added the --excessiveStackTrace:on to the nimble (nimble --excessiveStackTrace:on run) (no changes)

  What must I actually do?

---

• Araq (orginal) [2025-12-31T18:16:46+01:00] view original

  The pragma is the ` {.line: loc.}:` part.

---