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| author | Carlo Capocasa <carlo@capocasa.net> | 2022-06-11 18:23:31 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2022-06-11 18:23:31 +0200 |
| commit | e2e663a14389500b07e2f6fcd5c231536bdf76a0 (patch) | |
| tree | d4664542ea9e506a65eeb67511ca8aa097c1dc4d | |
| parent | ac89eead8a40a1a8ee170a4650a1d47e203da14c (diff) | |
| download | Nim-e2e663a14389500b07e2f6fcd5c231536bdf76a0.tar.gz | |
Friendlier error message with solution (#19880)
* Add helpful suggestion, should always apply * mention var param limitation in async docs * Update compiler/lambdalifting.nim whoops thanks Co-authored-by: flywind <43030857+xflywind@users.noreply.github.com> Co-authored-by: flywind <43030857+xflywind@users.noreply.github.com>
| -rw-r--r-- | compiler/lambdalifting.nim | 3 | ||||
| -rw-r--r-- | lib/pure/asyncdispatch.nim | 5 |
2 files changed, 7 insertions, 1 deletions
diff --git a/compiler/lambdalifting.nim b/compiler/lambdalifting.nim index 4b7ca89cd..96edba8c8 100644 --- a/compiler/lambdalifting.nim +++ b/compiler/lambdalifting.nim @@ -288,7 +288,8 @@ proc markAsClosure(g: ModuleGraph; owner: PSym; n: PNode) = if illegalCapture(s): localError(g.config, n.info, ("'$1' is of type <$2> which cannot be captured as it would violate memory" & - " safety, declared here: $3; using '-d:nimNoLentIterators' helps in some cases") % + " safety, declared here: $3; using '-d:nimNoLentIterators' helps in some cases." & + " Consider using a <ref $2> which can be captured.") % [s.name.s, typeToString(s.typ), g.config$s.info]) elif not (owner.typ.callConv == ccClosure or owner.typ.callConv == ccNimCall and tfExplicitCallConv notin owner.typ.flags): localError(g.config, n.info, "illegal capture '$1' because '$2' has the calling convention: <$3>" % diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim index 755f59ff7..0d406b271 100644 --- a/lib/pure/asyncdispatch.nim +++ b/lib/pure/asyncdispatch.nim @@ -98,6 +98,10 @@ ## `await`. The following section shows different ways that you can handle ## exceptions in async procs. ## +## .. caution:: +## Procedures marked {.async.} do not support mutable parameters such +## as `var int`. References such as `ref int` should be used instead. +## ## Handling Exceptions ## ------------------- ## @@ -192,6 +196,7 @@ ## ================ ## ## * The effect system (`raises: []`) does not work with async procedures. +## * Mutable parameters are not supported by async procedures. ## ## ## Multiple async backend support |