From 9dab88712f68d79ec81d87deb433094a3b9d0013 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adolfo=20Ochagav=C3=ADa?= <aochagavia92@gmail.com>
Date: Sun, 26 Oct 2014 16:29:27 +0100
Subject: [PATCH] Show a note when closure field is called as method
Closes https://github.com/rust-lang/rust/issues/18343
---
src/librustc/middle/typeck/check/method.rs | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/src/librustc/middle/typeck/check/method.rs b/src/librustc/middle/typeck/check/method.rs
index cb2f1e010ac..53a301cc94b 100644
--- a/src/librustc/middle/typeck/check/method.rs
+++ b/src/librustc/middle/typeck/check/method.rs
@@ -223,17 +223,37 @@ pub fn report_error(fcx: &FnCtxt,
{
match error {
NoMatch(static_sources) => {
+ let cx = fcx.tcx();
+ let method_ustring = method_name.user_string(cx);
+
+ // True if the type is a struct and contains a field with
+ // the same name as the not-found method
+ let is_field = match ty::get(rcvr_ty).sty {
+ ty_struct(did, _) =>
+ ty::lookup_struct_fields(cx, did)
+ .iter()
+ .any(|f| f.name.user_string(cx) == method_ustring),
+ _ => false
+ };
+
fcx.type_error_message(
span,
|actual| {
format!("type `{}` does not implement any \
method in scope named `{}`",
actual,
- method_name.user_string(fcx.tcx()))
+ method_ustring)
},
rcvr_ty,
None);
+ // If the method has the name of a field, give a help note
+ if is_field {
+ cx.sess.span_note(span,
+ format!("use `(s.{0})(...)` if you meant to call the \
+ function stored in the `{0}` field", method_ustring).as_slice());
+ }
+
if static_sources.len() > 0 {
fcx.tcx().sess.fileline_note(
span,