add custom pragma support for var and let symbols (#9582)

* add custom pragma support for var and let symbols
* updated changelog for custom pragmas on var and let symbols
* add oldast switch for backwards compatibility

1 files changed, 19 insertions, 4 deletions

diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 39f200ba8..12283e042 100644
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -330,9 +330,9 @@ proc semIdentDef(c: PContext, n: PNode, kind: TSymKind): PSym =
 proc checkNilable(c: PContext; v: PSym) =
   if {sfGlobal, sfImportC} * v.flags == {sfGlobal} and
       {tfNotNil, tfNeedsInit} * v.typ.flags != {}:
-    if v.ast.isNil:
+    if v.astdef.isNil:
       message(c.config, v.info, warnProveInit, v.name.s)
-    elif tfNotNil in v.typ.flags and tfNotNil notin v.ast.typ.flags:
+    elif tfNotNil in v.typ.flags and tfNotNil notin v.astdef.typ.flags:
       message(c.config, v.info, warnProveInit, v.name.s)
 
 include semasgn
@@ -518,8 +518,6 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
               message(c.config, a.info, warnShadowIdent, v.name.s)
       if a.kind != nkVarTuple:
         if def.kind != nkEmpty:
-          # this is needed for the evaluation pass and for the guard checking:
-          v.ast = def
           if sfThread in v.flags: localError(c.config, def.info, errThreadvarCannotInit)
         setVarType(c, v, typ)
         b = newNodeI(nkIdentDefs, a.info)
@@ -531,6 +529,23 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
         addSon(b, a.sons[length-2])
         addSon(b, copyTree(def))
         addToVarSection(c, result, n, b)
+        if optOldAst in c.config.options:
+          if def.kind != nkEmpty:
+            v.ast = def
+        else:
+          # this is needed for the evaluation pass, guard checking
+          #  and custom pragmas:
+          var ast = newNodeI(nkIdentDefs, a.info)
+          if a[j].kind == nkPragmaExpr:
+            var p = newNodeI(nkPragmaExpr, a.info)
+            p.add newSymNode(v)
+            p.add a[j][1].copyTree
+            ast.add p
+          else:
+            ast.add newSymNode(v)
+          ast.add a.sons[length-2].copyTree
+          ast.add def
+          v.ast = ast
       else:
         if def.kind in {nkPar, nkTupleConstr}: v.ast = def[j]
         # bug #7663, for 'nim check' this can be a non-tuple: