From 9273f59aa140e62163dc2f2787fd9163d3d7fee6 Mon Sep 17 00:00:00 2001
From: Janusz Marcinkiewicz <virrages@gmail.com>
Date: Sun, 22 Dec 2019 22:48:45 +0100
Subject: [PATCH] Extend suggestion span to whole method call

---
 src/librustc_resolve/late/diagnostics.rs | 26 ++++++++++++++----------
 src/test/ui/self/suggest-self-2.stderr   | 12 ++++++++---
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index 859307c51ed9f..bbe62758e3ae1 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -255,8 +255,7 @@ impl<'a> LateResolutionVisitor<'a, '_> {
             }
 
             // Check if the first argument is `self` and suggest calling a method.
-            let mut has_self_arg = false;
-            let mut args_span = None;
+            let mut has_self_arg = None;
             if let PathSource::Expr(parent) = source {
                 match &parent.map(|p| &p.kind) {
                     Some(ExprKind::Call(_, args)) if args.len() > 0 => {
@@ -264,13 +263,18 @@ impl<'a> LateResolutionVisitor<'a, '_> {
                         loop {
                             match expr_kind {
                                 ExprKind::Path(_, arg_name) if arg_name.segments.len() == 1 => {
-                                    has_self_arg = arg_name.segments[0].ident.name == kw::SelfLower;
-                                    if args.len() > 1 {
-                                        args_span = Some(Span::new(
-                                            args[1].span.lo(),
-                                            args.last().unwrap().span.hi(),
-                                            parent.unwrap().span.ctxt(),
-                                        ));
+                                    if arg_name.segments[0].ident.name == kw::SelfLower {
+                                        let call_span = parent.unwrap().span;
+                                        let args_span = if args.len() > 1 {
+                                            Some(Span::new(
+                                                args[1].span.lo(),
+                                                args.last().unwrap().span.hi(),
+                                                call_span.ctxt(),
+                                            ))
+                                        } else {
+                                            None
+                                        };
+                                        has_self_arg = Some((call_span, args_span));
                                     }
                                     break;
                                 },
@@ -283,7 +287,7 @@ impl<'a> LateResolutionVisitor<'a, '_> {
                 }
             };
 
-            if has_self_arg {
+            if let Some((call_span, args_span)) = has_self_arg {
                 let mut args_snippet: String = String::from("");
                 if let Some(args_span) = args_span {
                     if let Ok(snippet) = self.r.session.source_map().span_to_snippet(args_span) {
@@ -292,7 +296,7 @@ impl<'a> LateResolutionVisitor<'a, '_> {
                 }
 
                 err.span_suggestion(
-                    span,
+                    call_span,
                     &format!("try calling `{}` as a method", ident),
                     format!("self.{}({})", path_str, args_snippet),
                     Applicability::MachineApplicable,
diff --git a/src/test/ui/self/suggest-self-2.stderr b/src/test/ui/self/suggest-self-2.stderr
index 6148012ac0d92..452c31275153a 100644
--- a/src/test/ui/self/suggest-self-2.stderr
+++ b/src/test/ui/self/suggest-self-2.stderr
@@ -2,19 +2,25 @@ error[E0425]: cannot find function `bar` in this scope
   --> $DIR/suggest-self-2.rs:5:9
    |
 LL |         bar(self);
-   |         ^^^ help: try calling `bar` as a method: `self.bar()`
+   |         ^^^------
+   |         |
+   |         help: try calling `bar` as a method: `self.bar()`
 
 error[E0425]: cannot find function `bar` in this scope
   --> $DIR/suggest-self-2.rs:9:9
    |
 LL |         bar(&&self, 102);
-   |         ^^^ help: try calling `bar` as a method: `self.bar(102)`
+   |         ^^^-------------
+   |         |
+   |         help: try calling `bar` as a method: `self.bar(102)`
 
 error[E0425]: cannot find function `bar` in this scope
   --> $DIR/suggest-self-2.rs:13:9
    |
 LL |         bar(&mut self, 102, &"str");
-   |         ^^^ help: try calling `bar` as a method: `self.bar(102, &"str")`
+   |         ^^^------------------------
+   |         |
+   |         help: try calling `bar` as a method: `self.bar(102, &"str")`
 
 error[E0425]: cannot find function `bar` in this scope
   --> $DIR/suggest-self-2.rs:17:9