show symchoices as ambiguous in overload type mismatches (#24077)

fixes #23397

All ambiguous symbols generate symchoices for call arguments since
#23123. So, if a type mismatch receives a symchoice node for an
argument, we now treat it as an ambiguous identifier and list the
ambiguous symbols in the error message.

2 files changed, 27 insertions, 9 deletions

diff --git a/compiler/lookups.nim b/compiler/lookups.nim
index 0e576d765..2a48f6349 100644
--- a/compiler/lookups.nim
+++ b/compiler/lookups.nim
@@ -563,23 +563,33 @@ proc errorUseQualifier*(c: PContext; info: TLineInfo; s: PSym) =
   var amb: bool = false
   discard errorUseQualifier(c, info, s, amb)
 
-proc errorUseQualifier*(c: PContext; info: TLineInfo; candidates: seq[PSym]; prefix = "use one of") =
-  var err = "ambiguous identifier: '" & candidates[0].name.s & "'"
+proc ambiguousIdentifierMsg*(candidates: seq[PSym], prefix = "use one of", indent = 0): string =
+  result = ""
+  for i in 0 ..< indent:
+    result.add(' ')
+  result.add "ambiguous identifier: '" & candidates[0].name.s & "'"
   var i = 0
   for candidate in candidates:
-    if i == 0: err.add " -- $1 the following:\n" % prefix
-    else: err.add "\n"
-    err.add "  " & candidate.owner.name.s & "." & candidate.name.s
-    err.add ": " & typeToString(candidate.typ)
+    if i == 0: result.add " -- $1 the following:\n" % prefix
+    else: result.add "\n"
+    for i in 0 ..< indent:
+      result.add(' ')
+    result.add "  " & candidate.owner.name.s & "." & candidate.name.s
+    result.add ": " & typeToString(candidate.typ)
     inc i
-  localError(c.config, info, errGenerated, err)
 
-proc errorUseQualifier*(c: PContext; info:TLineInfo; choices: PNode) =
+proc errorUseQualifier*(c: PContext; info: TLineInfo; candidates: seq[PSym]) =
+  localError(c.config, info, errGenerated, ambiguousIdentifierMsg(candidates))
+
+proc ambiguousIdentifierMsg*(choices: PNode, indent = 0): string =
   var candidates = newSeq[PSym](choices.len)
   let prefix = if choices[0].typ.kind != tyProc: "use one of" else: "you need a helper proc to disambiguate"
   for i, n in choices:
     candidates[i] = n.sym
-  errorUseQualifier(c, info, candidates, prefix)
+  result = ambiguousIdentifierMsg(candidates, prefix, indent)
+
+proc errorUseQualifier*(c: PContext; info:TLineInfo; choices: PNode) =
+  localError(c.config, info, errGenerated, ambiguousIdentifierMsg(choices))
 
 proc errorUndeclaredIdentifier*(c: PContext; info: TLineInfo; name: string, extra = "") =
   var err: string
diff --git a/compiler/semcall.nim b/compiler/semcall.nim
index 06dd09b69..b81bc2a63 100644
--- a/compiler/semcall.nim
+++ b/compiler/semcall.nim
@@ -285,6 +285,8 @@ proc presentFailedCandidates(c: PContext, n: PNode, errors: CandidateErrors):
           candidates.add "\n"
         of kTypeMismatch:
           doAssert nArg != nil
+          if nArg.kind in nkSymChoices:
+            candidates.add ambiguousIdentifierMsg(nArg, indent = 2)
           let wanted = err.firstMismatch.formal.typ
           doAssert err.firstMismatch.formal != nil
           doAssert wanted != nil
@@ -317,6 +319,9 @@ proc presentFailedCandidates(c: PContext, n: PNode, errors: CandidateErrors):
           candidates.add renderTree(arg)
           candidates.add "' of type: "
           candidates.addTypeDeclVerboseMaybe(c.config, got)
+          if nArg.kind in nkSymChoices:
+            candidates.add "\n"
+            candidates.add ambiguousIdentifierMsg(nArg, indent = 2)
           if got != nil and got.kind == tyProc and wanted.kind == tyProc:
             # These are proc mismatches so,
             # add the extra explict detail of the mismatch
@@ -370,6 +375,9 @@ proc presentFailedCandidates(c: PContext, n: PNode, errors: CandidateErrors):
             candidates.add "' is of type: "
             let got = arg.typ
             candidates.addTypeDeclVerboseMaybe(c.config, got)
+            if arg.kind in nkSymChoices:
+              candidates.add "\n"
+              candidates.add ambiguousIdentifierMsg(arg, indent = 2)
             doAssert wanted != nil
             if got != nil:
               if got.kind == tyProc and wanted.kind == tyProc: