nicer error messages (untested)

1 files changed, 11 insertions, 9 deletions

diff --git a/compiler/sigmatch.nim b/compiler/sigmatch.nim
index b5e01811e..4a3773ed8 100644
--- a/compiler/sigmatch.nim
+++ b/compiler/sigmatch.nim
@@ -22,6 +22,7 @@ type
   TCandidateState* = enum 
     csEmpty, csMatch, csNoMatch
 
+  CandidateErrors* = seq[PSym]
   TCandidate* {.final.} = object
     c*: PContext
     exactMatches*: int       # also misused to prefer iters over procs
@@ -45,7 +46,7 @@ type
                              # a distrinct type
     typedescMatched: bool
     inheritancePenalty: int  # to prefer closest father object type
-    errors*: seq[string]     # additional clarifications to be displayed to the
+    errors*: CandidateErrors # additional clarifications to be displayed to the
                              # user if overload resolution fails
 
   TTypeRelation* = enum      # order is important!
@@ -202,16 +203,17 @@ proc writeMatches*(c: TCandidate) =
   writeln(stdout, "intconv matches: " & $c.intConvMatches)
   writeln(stdout, "generic matches: " & $c.genericMatches)
 
-proc argTypeToString(arg: PNode): string =
+proc argTypeToString(arg: PNode; prefer: TPreferedDesc): string =
   if arg.kind in nkSymChoices:
-    result = typeToString(arg[0].typ)
+    result = typeToString(arg[0].typ, prefer)
     for i in 1 .. <arg.len:
       result.add(" | ")
-      result.add typeToString(arg[i].typ)
+      result.add typeToString(arg[i].typ, prefer)
   else:
-    result = arg.typ.typeToString
+    result = arg.typ.typeToString(prefer)
 
-proc describeArgs*(c: PContext, n: PNode, startIdx = 1): string =
+proc describeArgs*(c: PContext, n: PNode, startIdx = 1;
+                   prefer: TPreferedDesc = preferName): string =
   result = ""
   for i in countup(startIdx, n.len - 1):
     var arg = n.sons[i]
@@ -227,7 +229,7 @@ proc describeArgs*(c: PContext, n: PNode, startIdx = 1): string =
         arg = c.semOperand(c, n.sons[i])
         n.sons[i] = arg
     if arg.typ.kind == tyError: return
-    add(result, argTypeToString(arg))
+    add(result, argTypeToString(arg, prefer))
     if i != sonsLen(n) - 1: add(result, ", ")
 
 proc typeRel*(c: var TCandidate, f, aOrig: PType, doBind = true): TTypeRelation
@@ -480,8 +482,8 @@ proc matchUserTypeClass*(c: PContext, m: var TCandidate,
     dummyParam.typ = dummyType
     addDecl(c, dummyParam)
 
-  var checkedBody = c.semTryExpr(c, body.n[3].copyTree, bufferErrors = false)
-  m.errors = bufferedMsgs
+  var checkedBody = c.semTryExpr(c, body.n[3].copyTree)
+  #m.errors = bufferedMsgs
   clearBufferedMsgs()
   if checkedBody == nil: return isNone