just wanna try this

compiler/sigmatch.nim

@@ -96,6 +96,7 @@ type
 
 const
   isNilConversion = isConvertible # maybe 'isIntConv' fits better?
+  maxInheritancePenalty = high(int) div 2
 
 proc markUsed*(c: PContext; info: TLineInfo, s: PSym; checkStyle = true)
 proc markOwnerModuleAsUsed*(c: PContext; s: PSym)
@@ -292,9 +293,9 @@ proc cmpInheritancePenalty(a, b: int): int =
   var eb = b
   var ea = a
   if b < 0:
-    eb = 100  # defacto max penalty
+    eb = maxInheritancePenalty
   if a < 0:
-    ea = 100
+    ea = maxInheritancePenalty
   eb - ea
 
 proc cmpCandidates*(a, b: TCandidate, isFormal=true): int =
@@ -308,7 +309,8 @@ proc cmpCandidates*(a, b: TCandidate, isFormal=true): int =
   if result != 0: return
   result = a.convMatches - b.convMatches
   if result != 0: return
-  result = cmpInheritancePenalty(a.inheritancePenalty, b.inheritancePenalty)
+
+  result = b.inheritancePenalty - a.inheritancePenalty
   if result != 0: return
   if isFormal:
     # check for generic subclass relation
@@ -1570,7 +1572,8 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
         if aAsObject.kind == tyObject and trIsOutParam notin flags:
           let baseType = aAsObject.base
           if baseType != nil:
-            inc c.inheritancePenalty, 1 + int(c.inheritancePenalty < 0)
+            assert c.inheritancePenalty > -1
+            inc c.inheritancePenalty
             let ret = typeRel(c, f, baseType, flags)
             return if ret in {isEqual,isGeneric}: isSubtype else: ret
 
@@ -1667,7 +1670,8 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
           depth = -1
 
       if depth >= 0:
-        inc c.inheritancePenalty, depth + int(c.inheritancePenalty < 0)
+        assert c.inheritancePenalty > -1
+        inc c.inheritancePenalty, depth
         # bug #4863: We still need to bind generic alias crap, so
         # we cannot return immediately:
         result = if depth == 0: isGeneric else: isSubtype