remove the need for the .procvar annotation

compiler/sempass2.nim

@@ -514,8 +514,17 @@ proc propagateEffects(tracked: PEffects, n: PNode, s: PSym) =
     markSideEffect(tracked, s)
   mergeLockLevels(tracked, n, s.getLockLevel)
 
+proc procVarcheck(n: PNode) =
+  if n.kind in nkSymChoices:
+    for x in n: procVarCheck(x)
+  elif n.kind == nkSym and n.sym.magic != mNone:
+    localError(n.info, errXCannotBePassedToProcVar, n.sym.name.s)
+
 proc notNilCheck(tracked: PEffects, n: PNode, paramType: PType) =
   let n = n.skipConv
+  procVarcheck skipConvAndClosure(n)
+  #elif n.kind in nkSymChoices:
+  #  echo "came here"
   if paramType != nil and tfNotNil in paramType.flags and
       n.typ != nil and tfNotNil notin n.typ.flags:
     if n.kind == nkAddr:

compiler/semstmts.nim

@@ -71,6 +71,7 @@ proc toCover(t: PType): BiggestInt =
   else:
     result = lengthOrd(skipTypes(t, abstractVar-{tyTypeDesc}))
 
+when false:
   proc performProcvarCheck(c: PContext, info: TLineInfo, s: PSym) =
     ## Checks that the given symbol is a proper procedure variable, meaning
     ## that it
@@ -83,7 +84,8 @@ proc performProcvarCheck(c: PContext, info: TLineInfo, s: PSym) =
             break outer
         localError(info, errXCannotBePassedToProcVar, s.name.s)
 
-proc semProcvarCheck(c: PContext, n: PNode) =
+template semProcvarCheck(c: PContext, n: PNode) =
+  when false:
     var n = n.skipConv
     if n.kind in nkSymChoices:
       for x in n:

doc/manual/types.txt

@@ -1003,16 +1003,6 @@ Nim supports these `calling conventions`:idx:\:
 
 Most calling conventions exist only for the Windows 32-bit platform.
 
-Assigning/passing a procedure to a procedural variable is only allowed if one
-of the following conditions hold:
-1) The procedure that is accessed resides in the current module.
-2) The procedure is marked with the ``procvar`` pragma (see `procvar pragma <#pragmas-procvar-pragma>`_).
-3) The procedure has a calling convention that differs from ``nimcall``.
-4) The procedure is anonymous.
-
-The rules' purpose is to prevent the case that extending a non-``procvar``
-procedure with default parameters breaks client code.
-
 The default calling convention is ``nimcall``, unless it is an inner proc (a
 proc inside of a proc). For an inner proc an analysis is performed whether it
 accesses its environment. If it does so, it has the calling convention

web/news/e031_version_0_16_2.rst

@@ -112,6 +112,12 @@ found `here <http://nim-lang.org/docs/manual.html#pragmas-used-pragma>`_.
 This is particularly useful for DSLs that help in tree construction.
 
 
+Language changes
+----------------
+
+- The ``.procvar`` annotation is not required anymore. That doesn't mean you
+  can pass ``system.$`` to ``map`` just yet though.
+
 
 Bugfixes
 --------