diff options
Diffstat (limited to 'src/libsyntax_ext')
| -rw-r--r-- | src/libsyntax_ext/deriving/encodable.rs | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/src/libsyntax_ext/deriving/encodable.rs b/src/libsyntax_ext/deriving/encodable.rs index 0e6e96438d8..743f22b6b31 100644 --- a/src/libsyntax_ext/deriving/encodable.rs +++ b/src/libsyntax_ext/deriving/encodable.rs @@ -190,7 +190,7 @@ fn encodable_substructure(cx: &mut ExtCtxt, Struct(_, ref fields) => { let emit_struct_field = cx.ident_of("emit_struct_field"); let mut stmts = Vec::new(); - for (i, &FieldInfo { name, ref self_, span, .. }) in fields.iter().enumerate() { + for (i, &FieldInfo { name, ref self_, span, attrs, .. }) in fields.iter().enumerate() { let name = match name { Some(id) => id.name, None => Symbol::intern(&format!("_field{}", i)), @@ -212,7 +212,19 @@ fn encodable_substructure(cx: &mut ExtCtxt, } else { cx.expr(span, ExprKind::Ret(Some(call))) }; - stmts.push(cx.stmt_expr(call)); + + // This exists for https://github.com/rust-lang/rust/pull/47540 + // + // If we decide to stabilize that flag this can be removed + let expr = if attrs.iter().any(|a| a.check_name("rustc_serialize_exclude_null")) { + let is_some = cx.ident_of("is_some"); + let condition = cx.expr_method_call(span, self_.clone(), is_some, vec![]); + cx.expr_if(span, condition, call, None) + } else { + call + }; + let stmt = cx.stmt_expr(expr); + stmts.push(stmt); } // unit structs have no fields and need to return Ok() |