Crash when trying to use a closure with error inside another closure

[starsiderfox]

Specification

When a closure has an error, the compiler crash when you try to pass it to a function while inside another closure.

Example

proc c*(x: proc()) =
    discard
    
proc a() =
    proc b() =
        foo
    proc x() =
        c(b)

Actual Output

nim.nim                  nim
nim.nim                  handleCmdLine
main.nim                 mainCommand
main.nim                 compileToBackend
main.nim                 commandCompileToC
modules.nim              compileProject
modules.nim              compileModule
passes.nim               processModule
passes.nim               processTopLevelStmt
sem.nim                  myProcess
sem.nim                  semStmtAndGenerateGenerics nkProcDef 386682 crash.nim(4, 0)
semstmts.nim             semStmt
semexprs.nim             semExprNoType
semexprs.nim             semExpr nkProcDef 386682 crash.nim(4, 0)
semstmts.nim             semRoutineDef nkProcDef 386682 crash.nim(4, 0)
semstmts.nim             semProc
semstmts.nim             semProcAux
semexprs.nim             semProcBody
semexprs.nim             semExpr nkStmtList 386690 crash.nim(5, 4)
semstmts.nim             semStmtList nkStmtList 386690 crash.nim(5, 4)
semexprs.nim             semExpr nkProcDef 386701 crash.nim(7, 4)
semstmts.nim             semRoutineDef nkProcDef 386701 crash.nim(7, 4)
semstmts.nim             semProc
semstmts.nim             semProcAux
sempass2.nim             trackProc
sempass2.nim             track
sempass2.nim             trackCall
sempass2.nim             trackOperandForIndirectCall
sempass2.nim             propagateEffects
fatal.nim                sysFatal
Error: unhandled exception: field 'sons' is not accessible for type 'TNode' using 'kind = nkError' [FieldDefect]

Expected Output

crash.nim(6, 9) Error: undeclared identifier: 'foo'

[zerbina]

The crash is due to missing error propagation for usage of procedure-like symbols outside of callee positions.

[zerbina]

As a side-note, neither b nor x are closures here, as both don't close over any local variable. The reason for c(x) needing to be nested in another inner procedure (for the crash to happen) is that sempass2 would not be run for the call otherwise, since the error in b properly propagates, disabling sempass2 for a.

The following:

proc c(x: proc()) =
  discard

proc b() =
  missing

c(b)

would also crash the compiler, but only when the maximum allowed number of errors is larger than 1 (which is the case for, e.g., check and nimsuggest).