fixes #798

compiler/hlo.nim

@@ -68,7 +68,8 @@ proc hlo(c: PContext, n: PNode): PNode =
     result = n
   else:
     if n.kind in {nkFastAsgn, nkAsgn, nkIdentDefs, nkVarTuple} and
-        n.sons[0].kind == nkSym and sfGlobal in n.sons[0].sym.flags:
+        n.sons[0].kind == nkSym and 
+        {sfGlobal, sfPure} * n.sons[0].sym.flags == {sfGlobal, sfPure}:
       # do not optimize 'var g {.global} = re(...)' again!
       return n
     result = applyPatterns(c, n)

tests/trmacros/tor.nim

@@ -1,6 +1,7 @@
 discard """
   output: '''3060
-true'''
+true
+3'''
 """
 
 template arithOps: expr = (`+` | `-` | `*`)
@@ -19,3 +20,9 @@ var
   c = false
 a = b and a
 echo a
+
+# bug #798
+template t012{(0|1|2){x}}(x: expr): expr = x+1
+let z = 1
+# outputs 3 thanks to fixpoint iteration:
+echo z