fix illegal recursion checks

compiler/types.nim

@@ -1145,7 +1145,9 @@ proc computeSizeAux(typ: PType, a: var biggestInt): biggestInt =
     result = ptrSize
     a = result
   of tyArray, tyArrayConstr:
-    result = lengthOrd(typ.sons[0]) * computeSizeAux(typ.sons[1], a)
+    let elemSize = computeSizeAux(typ.sons[1], a)
+    if elemSize < 0: return elemSize
+    result = lengthOrd(typ.sons[0]) * elemSize
   of tyEnum: 
     if firstOrd(typ) < 0: 
       result = 4              # use signed int32
@@ -1196,8 +1198,9 @@ proc computeSizeAux(typ: PType, a: var biggestInt): biggestInt =
   of tyGenericInst, tyDistinct, tyGenericBody, tyMutable, tyConst, tyIter:
     result = computeSizeAux(lastSon(typ), a)
   of tyTypeDesc:
-    result = (if typ.len == 1: computeSizeAux(typ.sons[0], a) else: -1)
-  of tyProxy: result = 1
+    result = if typ.len == 1: computeSizeAux(typ.sons[0], a)
+             else: szUnknownSize
+  of tyForward: return szIllegalRecursion
   else:
     #internalError("computeSizeAux()")
     result = szUnknownSize

tests/reject/tillrec.nim

@@ -14,4 +14,3 @@ type
     y: Int
     x: array[0..3, TIllegal]
 
-

tests/reject/typredef.nim

@@ -6,5 +6,3 @@ discard """
 type
   Uint8 = Uint8 #ERROR_MSG illegal recursion in type 'Uint8'
 
-
-