Merge remote-tracking branch 'nim-lang/devel' into emscripten-support

lib/pure/future.nim

@@ -75,7 +75,7 @@ macro `=>`*(p, b: expr): expr {.immediate.} =
         identDefs.add(newEmptyNode())
       of nnkIdent:
         identDefs.add(c)
-        identDefs.add(newEmptyNode())
+        identDefs.add(newIdentNode("auto"))
         identDefs.add(newEmptyNode())
       of nnkInfix:
         if c[0].kind == nnkIdent and c[0].ident == !"->":
@@ -93,7 +93,7 @@ macro `=>`*(p, b: expr): expr {.immediate.} =
   of nnkIdent:
     var identDefs = newNimNode(nnkIdentDefs)
     identDefs.add(p)
-    identDefs.add(newEmptyNode())
+    identDefs.add(newIdentNode("auto"))
     identDefs.add(newEmptyNode())
     params.add(identDefs)
   of nnkInfix:

lib/system.nim

@@ -2235,7 +2235,9 @@ proc `$`*[T: tuple|object](x: T): string =
     firstElement = false
   result.add(")")
 
-proc collectionToString[T](x: T, b, e: string): string =
+proc collectionToString[T: set | seq](x: T, b, e: string): string =
+  when x is seq:
+    if x.isNil: return "nil"
   result = b
   var firstElement = true
   for value in items(x):