diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 3b6e6db7f46c..ca5d3f55a0fe 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -12,7 +12,7 @@ use self::Destination::*;
 
 use syntax_pos::{DUMMY_SP, FileMap, Span, MultiSpan};
 
-use {Level, CodeSuggestion, DiagnosticBuilder, SubDiagnostic, CodeMapper, DiagnosticId};
+use {Level, CodeSuggestion, DiagnosticBuilder, SubDiagnostic, CodeMapperDyn, DiagnosticId};
 use snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, StyledString, Style};
 use styled_buffer::StyledBuffer;
 
@@ -120,7 +120,7 @@ impl ColorConfig {
 
 pub struct EmitterWriter {
     dst: Destination,
-    cm: Option<Lrc<CodeMapper>>,
+    cm: Option<Lrc<CodeMapperDyn>>,
     short_message: bool,
     teach: bool,
     ui_testing: bool,
@@ -134,7 +134,7 @@ struct FileWithAnnotatedLines {
 
 impl EmitterWriter {
     pub fn stderr(color_config: ColorConfig,
-                  code_map: Option<Lrc<CodeMapper>>,
+                  code_map: Option<Lrc<CodeMapperDyn>>,
                   short_message: bool,
                   teach: bool)
                   -> EmitterWriter {
@@ -149,7 +149,7 @@ impl EmitterWriter {
     }
 
     pub fn new(dst: Box<Write + Send>,
-               code_map: Option<Lrc<CodeMapper>>,
+               code_map: Option<Lrc<CodeMapperDyn>>,
                short_message: bool,
                teach: bool)
                -> EmitterWriter {
@@ -1195,8 +1195,6 @@ impl EmitterWriter {
                                level: &Level,
                                max_line_num_len: usize)
                                -> io::Result<()> {
-        use std::borrow::Borrow;
-
         if let Some(ref cm) = self.cm {
             let mut buffer = StyledBuffer::new();
 
@@ -1213,7 +1211,7 @@ impl EmitterWriter {
                                Some(Style::HeaderMsg));
 
             // Render the replacements for each suggestion
-            let suggestions = suggestion.splice_lines(cm.borrow());
+            let suggestions = suggestion.splice_lines(&**cm);
 
             let mut row_num = 2;
             for &(ref complete, ref parts) in suggestions.iter().take(MAX_SUGGESTIONS) {
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index 7148969191f2..a25c3668bb13 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -36,7 +36,7 @@ use self::Level::*;
 
 use emitter::{Emitter, EmitterWriter};
 
-use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::sync::{self, Lrc};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::stable_hasher::StableHasher;
 
@@ -106,6 +106,8 @@ pub struct SubstitutionPart {
     pub snippet: String,
 }
 
+pub type CodeMapperDyn = CodeMapper + sync::Send + sync::Sync;
+
 pub trait CodeMapper {
     fn lookup_char_pos(&self, pos: BytePos) -> Loc;
     fn span_to_lines(&self, sp: Span) -> FileLinesResult;
@@ -119,7 +121,8 @@ pub trait CodeMapper {
 
 impl CodeSuggestion {
     /// Returns the assembled code suggestions and whether they should be shown with an underline.
-    pub fn splice_lines(&self, cm: &CodeMapper) -> Vec<(String, Vec<SubstitutionPart>)> {
+    pub fn splice_lines(&self, cm: &CodeMapperDyn)
+                        -> Vec<(String, Vec<SubstitutionPart>)> {
         use syntax_pos::{CharPos, Loc, Pos};
 
         fn push_trailing(buf: &mut String,
@@ -290,7 +293,7 @@ impl Handler {
     pub fn with_tty_emitter(color_config: ColorConfig,
                             can_emit_warnings: bool,
                             treat_err_as_bug: bool,
-                            cm: Option<Lrc<CodeMapper>>)
+                            cm: Option<Lrc<CodeMapperDyn>>)
                             -> Handler {
         Handler::with_tty_emitter_and_flags(
             color_config,
@@ -303,7 +306,7 @@ impl Handler {
     }
 
     pub fn with_tty_emitter_and_flags(color_config: ColorConfig,
-                                      cm: Option<Lrc<CodeMapper>>,
+                                      cm: Option<Lrc<CodeMapperDyn>>,
                                       flags: HandlerFlags)
                                       -> Handler {
         let emitter = Box::new(EmitterWriter::stderr(color_config, cm, false, false));
diff --git a/src/libsyntax/json.rs b/src/libsyntax/json.rs
index eed3c6914054..b4f34fb12e36 100644
--- a/src/libsyntax/json.rs
+++ b/src/libsyntax/json.rs
@@ -26,7 +26,7 @@ use errors::{DiagnosticBuilder, SubDiagnostic, CodeSuggestion, CodeMapper};
 use errors::DiagnosticId;
 use errors::emitter::{Emitter, EmitterWriter};
 
-use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::sync::{self, Lrc};
 use std::io::{self, Write};
 use std::vec;
 use std::sync::{Arc, Mutex};
@@ -36,7 +36,7 @@ use rustc_serialize::json::{as_json, as_pretty_json};
 pub struct JsonEmitter {
     dst: Box<Write + Send>,
     registry: Option<Registry>,
-    cm: Lrc<CodeMapper + 'static>,
+    cm: Lrc<CodeMapper + sync::Send + sync::Sync>,
     pretty: bool,
     /// Whether "approximate suggestions" are enabled in the config
     approximate_suggestions: bool,