3 files changed, 15 insertions, 4 deletions
diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 9cf206b4c..976d7c757 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -998,7 +998,7 @@ proc afterCallActions(c: PContext; n, orig: PNode, flags: TExprFlags; expectedTy
     fixAbstractType(c, result)
     analyseIfAddressTakenInCall(c, result)
     if callee.magic != mNone:
-      result = magicsAfterOverloadResolution(c, result, flags)
+      result = magicsAfterOverloadResolution(c, result, flags, expectedType)
     when false:
       if result.typ != nil and
           not (result.typ.kind == tySequence and result.typ[0].kind == tyEmpty):
diff --git a/compiler/seminst.nim b/compiler/seminst.nim
index b5fe244b0..25e5b267e 100644
--- a/compiler/seminst.nim
+++ b/compiler/seminst.nim
@@ -127,11 +127,18 @@ proc instantiateBody(c: PContext, n, params: PNode, result, orig: PSym) =
         if sfGenSym in param.flags:
           idTablePut(symMap, params[i].sym, result.typ.n[param.position+1].sym)
     freshGenSyms(c, b, result, orig, symMap)
-    
+
     if sfBorrow notin orig.flags: 
       # We do not want to generate a body for generic borrowed procs.
       # As body is a sym to the borrowed proc.
-      b = semProcBody(c, b)
+      let resultType = # todo probably refactor it into a function
+        if result.kind == skMacro:
+          sysTypeFromName(c.graph, n.info, "NimNode")
+        elif not isInlineIterator(result.typ):
+          result.typ[0]
+        else:
+          nil
+      b = semProcBody(c, b, resultType)
     result.ast[bodyPos] = hloBody(c, b)
     excl(result.flags, sfForward)
     trackProc(c, result, result.ast[bodyPos])
diff --git a/compiler/semmagic.nim b/compiler/semmagic.nim
index 751ca8fe7..b4c6cd275 100644
--- a/compiler/semmagic.nim
+++ b/compiler/semmagic.nim
@@ -526,7 +526,7 @@ proc checkDefault(c: PContext, n: PNode): PNode =
     message(c.config, n.info, warnUnsafeDefault, typeToString(constructed))
 
 proc magicsAfterOverloadResolution(c: PContext, n: PNode,
-                                   flags: TExprFlags): PNode =
+                                   flags: TExprFlags; expectedType: PType = nil): PNode =
   ## This is the preferred code point to implement magics.
   ## ``c`` the current module, a symbol table to a very good approximation
   ## ``n`` the ast like it would be passed to a real macro
@@ -635,5 +635,9 @@ proc magicsAfterOverloadResolution(c: PContext, n: PNode,
     result = n
   of mPrivateAccess:
     result = semPrivateAccess(c, n)
+  of mArrToSeq:
+    result = n
+    if result.typ != nil and expectedType != nil and result.typ.kind == tySequence and expectedType.kind == tySequence and result.typ[0].kind == tyEmpty:
+      result.typ = expectedType # type inference for empty sequence # bug #21377
   else:
     result = n