From 1dc13e4ad4a140ae1ac4d84e13411c7406196926 Mon Sep 17 00:00:00 2001 From: Piotr Jawniak Date: Sun, 1 Jun 2014 14:16:11 +0200 Subject: Fix deriving Encodable trait for unit structs Closes #14021 --- src/libsyntax/ext/deriving/encodable.rs | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'src/libsyntax') diff --git a/src/libsyntax/ext/deriving/encodable.rs b/src/libsyntax/ext/deriving/encodable.rs index d6b7e84b535..4f92dff0c59 100644 --- a/src/libsyntax/ext/deriving/encodable.rs +++ b/src/libsyntax/ext/deriving/encodable.rs @@ -175,6 +175,14 @@ fn encodable_substructure(cx: &mut ExtCtxt, trait_span: Span, stmts.push(cx.stmt_expr(call)); } + // unit structs have no fields and need to return Ok() + if stmts.is_empty() { + let ret_ok = cx.expr(trait_span, + ExprRet(Some(cx.expr_ok(trait_span, + cx.expr_lit(trait_span, LitNil))))); + stmts.push(cx.stmt_expr(ret_ok)); + } + let blk = cx.lambda_stmts_1(trait_span, stmts, blkarg); cx.expr_method_call(trait_span, encoder, -- cgit 1.4.1-3-g733a5