'func' is now an alias for 'proc .noSideEffect'

changelog.md

@@ -35,6 +35,7 @@
 
 - Dot calls combined with explicit generic instantiations can now be written
   as ``x.y[:z]``. ``x.y[:z]`` that is transformed into ``y[z](x)`` in the parser.
+- ``func`` is now an alias for ``proc {.noSideEffect.}``.
 
 ### Language changes
 

compiler/semstmts.nim

@@ -1513,7 +1513,9 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind,
     n.sons[patternPos] = semPattern(c, n.sons[patternPos])
   if s.kind == skIterator:
     s.typ.flags.incl(tfIterator)
-
+  elif s.kind == skFunc:
+    incl(s.flags, sfNoSideEffect)
+    incl(s.typ.flags, tfNoSideEffect)
   var proto = searchForProc(c, oldScope, s)
   if proto == nil or isAnon:
     if s.kind == skIterator: