fixes #1902

compiler/semfields.nim

@@ -19,12 +19,13 @@ type
 
 proc instFieldLoopBody(c: TFieldInstCtx, n: PNode, forLoop: PNode): PNode =
   case n.kind
-  of nkEmpty..pred(nkIdent), succ(nkIdent)..nkNilLit: result = n
-  of nkIdent:
+  of nkEmpty..pred(nkIdent), succ(nkSym)..nkNilLit: result = n
+  of nkIdent, nkSym:
     result = n
+    let ident = considerQuotedIdent(n)
     var L = sonsLen(forLoop)
     if c.replaceByFieldName:
-      if n.ident.id == forLoop[0].ident.id:
+      if ident.id == considerQuotedIdent(forLoop[0]).id:
         let fieldName = if c.tupleType.isNil: c.field.name.s
                         elif c.tupleType.n.isNil: "Field" & $c.tupleIndex
                         else: c.tupleType.n.sons[c.tupleIndex].sym.name.s
@@ -32,7 +33,7 @@ proc instFieldLoopBody(c: TFieldInstCtx, n: PNode, forLoop: PNode): PNode =
         return
     # other fields:
     for i in ord(c.replaceByFieldName)..L-3:
-      if n.ident.id == forLoop[i].ident.id:
+      if ident.id == considerQuotedIdent(forLoop[i]).id:
         var call = forLoop.sons[L-2]
         var tupl = call.sons[i+1-ord(c.replaceByFieldName)]
         if c.field.isNil:

tests/fields/tfields_in_template.nim

@@ -0,0 +1,15 @@
+discard """
+  output: '''n
+n'''
+"""
+
+# bug #1902
+# This works.
+for name, value in (n: "v").fieldPairs:
+  echo name
+
+# This doesn't compile - "expression 'name' has no type (or is ambiguous)".
+template wrapper: stmt =
+  for name, value in (n: "v").fieldPairs:
+    echo name
+wrapper()