fix #7446 Generics: type mismatch 'SomeunsignedInt or Natural' (#20522)

* fix #7446 Generics: type mismatch 'SomeunsignedInt or Natural'

* try fix

compiler/sigmatch.nim

@@ -1595,10 +1595,9 @@ proc typeRel(c: var TCandidate, f, aOrig: PType,
         c.inheritancePenalty = 0
         let x = typeRel(c, branch, aOrig, flags)
         maxInheritance = max(maxInheritance, c.inheritancePenalty)
-
         # 'or' implies maximum matching result:
         if x > result: result = x
-      if result >= isSubtype:
+      if result >= isIntConv:
         if result > isGeneric: result = isGeneric
         bindingRet result
       else:

tests/generics/t7446.nim

@@ -0,0 +1,10 @@
+proc foo(x: Natural or SomeUnsignedInt):int = 
+  when x is int:
+    result = 1
+  else:
+    result = 2
+let a = 10
+doAssert foo(a) == 1
+
+let b = 10'u8
+doAssert foo(b) == 2