Add flag to hide code on inline suggestions

Now there's a way to add suggestions that hide the suggested code when
presented inline, to avoid weird wording when short code snippets are
added at the end.

src/librustc_errors/diagnostic.rs

@@ -209,6 +209,22 @@ impl Diagnostic {
         self
     }
 
+    /// Prints out a message with a suggested edit of the code. If the suggestion is presented
+    /// inline it will only show the text message and not the text.
+    ///
+    /// See `diagnostic::CodeSuggestion` for more information.
+    pub fn span_suggestion_short(&mut self, sp: Span, msg: &str, suggestion: String) -> &mut Self {
+        self.suggestions.push(CodeSuggestion {
+            substitution_parts: vec![Substitution {
+                span: sp,
+                substitutions: vec![suggestion],
+            }],
+            msg: msg.to_owned(),
+            show_code_when_inline: false,
+        });
+        self
+    }
+
     /// Prints out a message with a suggested edit of the code.
     ///
     /// See `diagnostic::CodeSuggestion` for more information.
@@ -219,6 +235,7 @@ impl Diagnostic {
                 substitutions: vec![suggestion],
             }],
             msg: msg.to_owned(),
+            show_code_when_inline: true,
         });
         self
     }
@@ -230,6 +247,7 @@ impl Diagnostic {
                 substitutions: suggestions,
             }],
             msg: msg.to_owned(),
+            show_code_when_inline: true,
         });
         self
     }

src/librustc_errors/diagnostic_builder.rs

@@ -146,6 +146,11 @@ impl<'a> DiagnosticBuilder<'a> {
                                                   sp: S,
                                                   msg: &str)
                                                   -> &mut Self);
+    forward!(pub fn span_suggestion_short(&mut self,
+                                          sp: Span,
+                                          msg: &str,
+                                          suggestion: String)
+                                          -> &mut Self);
     forward!(pub fn span_suggestion(&mut self,
                                     sp: Span,
                                     msg: &str,

src/librustc_errors/emitter.rs

@@ -47,8 +47,9 @@ impl Emitter for EmitterWriter {
                // don't display multiline suggestions as labels
                sugg.substitution_parts[0].substitutions[0].find('\n').is_none() {
                 let substitution = &sugg.substitution_parts[0].substitutions[0];
-                let msg = if substitution.len() == 0 {
-                    // This substitution is only removal, don't show it
+                let msg = if substitution.len() == 0 || !sugg.show_code_when_inline {
+                    // This substitution is only removal or we explicitely don't want to show the
+                    // code inline, don't show it
                     format!("help: {}", sugg.msg)
                 } else {
                     format!("help: {} `{}`", sugg.msg, substitution)

src/librustc_errors/lib.rs

@@ -84,6 +84,7 @@ pub struct CodeSuggestion {
     /// ```
     pub substitution_parts: Vec<Substitution>,
     pub msg: String,
+    pub show_code_when_inline: bool,
 }
 
 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]

src/libsyntax/parse/parser.rs

@@ -2807,9 +2807,9 @@ impl<'a> Parser<'a> {
                         let cur_pos = cm.lookup_char_pos(self.span.lo);
                         let op_pos = cm.lookup_char_pos(cur_op_span.hi);
                         if cur_pos.line != op_pos.line {
-                            err.span_suggestion(cur_op_span,
-                                                "did you mean to end the statement here instead?",
-                                                ";".to_string());
+                            err.span_suggestion_short(cur_op_span,
+                                                      "did you mean to use `;` here?",
+                                                      ";".to_string());
                         }
                         return Err(err);
                     }

src/test/ui/issue-22644.stderr

@@ -100,5 +100,5 @@ error: expected type, found `4`
   --> $DIR/issue-22644.rs:38:28
    |
 38 |     println!("{}", a: &mut 4);
-   |                            ^
+   |                            ^ expecting a type here because of type ascription
 

src/test/ui/suggestions/type-ascription-instead-of-statement-end.stderr

@@ -2,7 +2,7 @@ error: expected type, found `0`
   --> $DIR/type-ascription-instead-of-statement-end.rs:15:5
    |
 14 |     println!("test"):
-   |                     - help: did you mean to end the statement here instead? `;`
+   |                     - help: did you mean to use `;` here?
 15 |     0;
    |     ^ expecting a type here because of type ascription