bugfix: 'T = ref T' is an illegal recursive type

compiler/semexprs.nim

@@ -367,6 +367,7 @@ proc isOpImpl(c: PContext, n: PNode): PNode =
       result = newIntNode(nkIntLit, ord(t.kind == tyProc and
                                         t.callConv == ccClosure and 
                                         tfIterator notin t.flags))
+    else: discard
   else:
     var t2 = n[2].typ.skipTypes({tyTypeDesc})
     maybeLiftType(t2, c, n.info)

compiler/semfold.nim

@@ -255,6 +255,7 @@ proc evalIs(n, a: PNode): PNode =
       result = newIntNode(nkIntLit, ord(t.kind == tyProc and
                                         t.callConv == ccClosure and 
                                         tfIterator in t.flags))
+    else: discard
   else:
     # XXX semexprs.isOpImpl is slightly different and requires a context. yay.
     let t2 = n[2].typ

compiler/types.nim

@@ -1209,7 +1209,8 @@ proc computeSizeAux(typ: PType, a: var BiggestInt): BiggestInt =
     a = ptrSize
   of tyNil, tyCString, tyString, tySequence, tyPtr, tyRef, tyVar, tyOpenArray,
      tyBigNum:
-    result = ptrSize
+    if typ.lastSon == typ: result = szIllegalRecursion
+    else: result = ptrSize
     a = result
   of tyArray, tyArrayConstr:
     let elemSize = computeSizeAux(typ.sons[1], a)

todo.txt

@@ -2,7 +2,10 @@ version 0.10
 ============
 
 - Test nimfix on various babel packages
+
+- bug: 'type T = ref T' not recognized as illegal recursion
 - deprecate recursive tuples; tuple needs laxer type checking
+
 - VM: Pegs do not work at compile-time
 - VM: ptr/ref T cannot work in general
 
@@ -44,7 +47,6 @@ Bugs
 ====
 
 - scopes are still broken for generic instantiation!
-- bug: 'type T = ref T' not recognized as illegal recursion
 - bug: type conversions concerning proc types are weird
 - compilation of niminst takes way too long. looks like a regression
 - docgen: sometimes effects are listed twice

web/news.txt

@@ -49,6 +49,7 @@ News
     be used instead.
   - String case (or any non-ordinal case) statements 
     without 'else' are deprecated.
+  - Recursive tuple types are deprecated. Use ``object`` instead.
 
 
   Language Additions