Fix the start/end byte positions in the compiler JSON output

src/librustc/ich/impls_syntax.rs

@@ -424,6 +424,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
             ref lines,
             ref multibyte_chars,
             ref non_narrow_chars,
+            ref normalized_pos,
         } = *self;
 
         (name_hash as u64).hash_stable(hcx, hasher);
@@ -452,6 +453,12 @@ impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
         for &char_pos in non_narrow_chars.iter() {
             stable_non_narrow_char(char_pos, start_pos).hash_stable(hcx, hasher);
         }
+
+        normalized_pos.len().hash_stable(hcx, hasher);
+        for &char_pos in normalized_pos.iter() {
+            stable_normalized_pos(char_pos, start_pos).hash_stable(hcx, hasher);
+        }
+
     }
 }
 
@@ -481,6 +488,18 @@ fn stable_non_narrow_char(swc: ::syntax_pos::NonNarrowChar,
     (pos.0 - source_file_start.0, width as u32)
 }
 
+fn stable_normalized_pos(np: ::syntax_pos::NormalizedPos,
+                         source_file_start: ::syntax_pos::BytePos)
+                         -> (u32, u32) {
+    let ::syntax_pos::NormalizedPos {
+        pos,
+        diff
+    } = np;
+
+    (pos.0 - source_file_start.0, diff)
+}
+
+
 impl<'tcx> HashStable<StableHashingContext<'tcx>> for feature_gate::Features {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'tcx>, hasher: &mut StableHasher) {
         // Unfortunately we cannot exhaustively list fields here, since the

src/librustc_metadata/decoder.rs

@@ -1317,6 +1317,7 @@ impl<'a, 'tcx> CrateMetadata {
                                       mut lines,
                                       mut multibyte_chars,
                                       mut non_narrow_chars,
+                                      mut normalized_pos,
                                       name_hash,
                                       .. } = source_file_to_import;
 
@@ -1336,6 +1337,9 @@ impl<'a, 'tcx> CrateMetadata {
             for swc in &mut non_narrow_chars {
                 *swc = *swc - start_pos;
             }
+            for np in &mut normalized_pos {
+                np.pos = np.pos - start_pos;
+            }
 
             let local_version = local_source_map.new_imported_source_file(name,
                                                                    name_was_remapped,
@@ -1345,7 +1349,8 @@ impl<'a, 'tcx> CrateMetadata {
                                                                    source_length,
                                                                    lines,
                                                                    multibyte_chars,
-                                                                   non_narrow_chars);
+                                                                   non_narrow_chars,
+                                                                   normalized_pos);
             debug!("CrateMetaData::imported_source_files alloc \
                     source_file {:?} original (start_pos {:?} end_pos {:?}) \
                     translated (start_pos {:?} end_pos {:?})",

src/libsyntax/json.rs

@@ -25,6 +25,9 @@ use std::sync::{Arc, Mutex};
 
 use rustc_serialize::json::{as_json, as_pretty_json};
 
+#[cfg(test)]
+mod tests;
+
 pub struct JsonEmitter {
     dst: Box<dyn Write + Send>,
     registry: Option<Registry>,
@@ -332,8 +335,8 @@ impl DiagnosticSpan {
 
         DiagnosticSpan {
             file_name: start.file.name.to_string(),
-            byte_start: span.lo().0 - start.file.start_pos.0,
-            byte_end: span.hi().0 - start.file.start_pos.0,
+            byte_start: start.file.original_relative_byte_pos(span.lo()).0,
+            byte_end: start.file.original_relative_byte_pos(span.hi()).0,
             line_start: start.line,
             line_end: end.line,
             column_start: start.col.0 + 1,

src/libsyntax/json/tests.rs

@@ -0,0 +1,186 @@
+use super::*;
+
+use crate::json::JsonEmitter;
+use crate::source_map::{FilePathMapping, SourceMap};
+use crate::tests::Shared;
+use crate::with_default_globals;
+
+use errors::emitter::{ColorConfig, HumanReadableErrorType};
+use errors::Handler;
+use rustc_serialize::json::decode;
+use syntax_pos::{BytePos, Span};
+
+use std::str;
+
+#[derive(RustcDecodable, Debug, PartialEq, Eq)]
+struct TestData {
+    spans: Vec<SpanTestData>,
+}
+
+#[derive(RustcDecodable, Debug, PartialEq, Eq)]
+struct SpanTestData {
+    pub byte_start: u32,
+    pub byte_end: u32,
+    pub line_start: u32,
+    pub column_start: u32,
+    pub line_end: u32,
+    pub column_end: u32,
+}
+
+/// Test the span yields correct positions in JSON.
+fn test_positions(code: &str, span: (u32, u32), expected_output: SpanTestData) {
+    let expected_output = TestData { spans: vec![expected_output] };
+
+    with_default_globals(|| {
+        let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
+        sm.new_source_file(Path::new("test.rs").to_owned().into(), code.to_owned());
+
+        let output = Arc::new(Mutex::new(Vec::new()));
+        let je = JsonEmitter::new(
+            Box::new(Shared { data: output.clone() }),
+            None,
+            sm,
+            true,
+            HumanReadableErrorType::Short(ColorConfig::Never),
+            false,
+        );
+
+        let span = Span::with_root_ctxt(BytePos(span.0), BytePos(span.1));
+        let handler = Handler::with_emitter(true, None, Box::new(je));
+        handler.span_err(span, "foo");
+
+        let bytes = output.lock().unwrap();
+        let actual_output = str::from_utf8(&bytes).unwrap();
+        let actual_output: TestData = decode(actual_output).unwrap();
+
+        assert_eq!(expected_output, actual_output)
+    })
+}
+
+#[test]
+fn empty() {
+    test_positions(
+        " ",
+        (0, 1),
+        SpanTestData {
+            byte_start: 0,
+            byte_end: 1,
+            line_start: 1,
+            column_start: 1,
+            line_end: 1,
+            column_end: 2,
+        },
+    )
+}
+
+#[test]
+fn bom() {
+    test_positions(
+        "\u{feff} ",
+        (0, 1),
+        SpanTestData {
+            byte_start: 3,
+            byte_end: 4,
+            line_start: 1,
+            column_start: 1,
+            line_end: 1,
+            column_end: 2,
+        },
+    )
+}
+
+#[test]
+fn lf_newlines() {
+    test_positions(
+        "\nmod foo;\nmod bar;\n",
+        (5, 12),
+        SpanTestData {
+            byte_start: 5,
+            byte_end: 12,
+            line_start: 2,
+            column_start: 5,
+            line_end: 3,
+            column_end: 3,
+        },
+    )
+}
+
+#[test]
+fn crlf_newlines() {
+    test_positions(
+        "\r\nmod foo;\r\nmod bar;\r\n",
+        (5, 12),
+        SpanTestData {
+            byte_start: 6,
+            byte_end: 14,
+            line_start: 2,
+            column_start: 5,
+            line_end: 3,
+            column_end: 3,
+        },
+    )
+}
+
+#[test]
+fn crlf_newlines_with_bom() {
+    test_positions(
+        "\u{feff}\r\nmod foo;\r\nmod bar;\r\n",
+        (5, 12),
+        SpanTestData {
+            byte_start: 9,
+            byte_end: 17,
+            line_start: 2,
+            column_start: 5,
+            line_end: 3,
+            column_end: 3,
+        },
+    )
+}
+
+#[test]
+fn span_before_crlf() {
+    test_positions(
+        "foo\r\nbar",
+        (2, 3),
+        SpanTestData {
+            byte_start: 2,
+            byte_end: 3,
+            line_start: 1,
+            column_start: 3,
+            line_end: 1,
+            column_end: 4,
+        },
+    )
+}
+
+#[test]
+fn span_on_crlf() {
+    test_positions(
+        "foo\r\nbar",
+        (3, 4),
+        SpanTestData {
+            byte_start: 3,
+            byte_end: 5,
+            line_start: 1,
+            column_start: 4,
+            line_end: 2,
+            column_end: 1,
+        },
+    )
+}
+
+#[test]
+fn span_after_crlf() {
+    test_positions(
+        "foo\r\nbar",
+        (4, 5),
+        SpanTestData {
+            byte_start: 5,
+            byte_end: 6,
+            line_start: 2,
+            column_start: 1,
+            line_end: 2,
+            column_end: 2,
+        },
+    )
+}

src/libsyntax/source_map.rs

@@ -283,6 +283,7 @@ impl SourceMap {
         mut file_local_lines: Vec<BytePos>,
         mut file_local_multibyte_chars: Vec<MultiByteChar>,
         mut file_local_non_narrow_chars: Vec<NonNarrowChar>,
+        mut file_local_normalized_pos: Vec<NormalizedPos>,
     ) -> Lrc<SourceFile> {
         let start_pos = self.next_start_pos();
 
@@ -301,6 +302,10 @@ impl SourceMap {
             *swc = *swc + start_pos;
         }
 
+        for nc in &mut file_local_normalized_pos {
+            nc.pos = nc.pos + start_pos;
+        }
+
         let source_file = Lrc::new(SourceFile {
             name: filename,
             name_was_remapped,
@@ -314,6 +319,7 @@ impl SourceMap {
             lines: file_local_lines,
             multibyte_chars: file_local_multibyte_chars,
             non_narrow_chars: file_local_non_narrow_chars,
+            normalized_pos: file_local_normalized_pos,
             name_hash,
         });
 

src/libsyntax/tests.rs

@@ -110,8 +110,8 @@ struct SpanLabel {
     label: &'static str,
 }
 
-struct Shared<T: Write> {
-    data: Arc<Mutex<T>>,
+crate struct Shared<T: Write> {
+    pub data: Arc<Mutex<T>>,
 }
 
 impl<T: Write> Write for Shared<T> {

src/libsyntax_pos/lib.rs

@@ -855,6 +855,15 @@ impl Sub<BytePos> for NonNarrowChar {
     }
 }
 
+/// Identifies an offset of a character that was normalized away from `SourceFile`.
+#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq, Debug)]
+pub struct NormalizedPos {
+    /// The absolute offset of the character in the `SourceMap`.
+    pub pos: BytePos,
+    /// The difference between original and normalized string at position.
+    pub diff: u32,
+}
+
 /// The state of the lazy external source loading mechanism of a `SourceFile`.
 #[derive(PartialEq, Eq, Clone)]
 pub enum ExternalSource {
@@ -918,6 +927,8 @@ pub struct SourceFile {
     pub multibyte_chars: Vec<MultiByteChar>,
     /// Width of characters that are not narrow in the source code.
     pub non_narrow_chars: Vec<NonNarrowChar>,
+    /// Locations of characters removed during normalization.
+    pub normalized_pos: Vec<NormalizedPos>,
     /// A hash of the filename, used for speeding up hashing in incremental compilation.
     pub name_hash: u128,
 }
@@ -984,6 +995,9 @@ impl Encodable for SourceFile {
             })?;
             s.emit_struct_field("name_hash", 8, |s| {
                 self.name_hash.encode(s)
+            })?;
+            s.emit_struct_field("normalized_pos", 9, |s| {
+                self.normalized_pos.encode(s)
             })
         })
     }
@@ -1034,6 +1048,8 @@ impl Decodable for SourceFile {
                 d.read_struct_field("non_narrow_chars", 7, |d| Decodable::decode(d))?;
             let name_hash: u128 =
                 d.read_struct_field("name_hash", 8, |d| Decodable::decode(d))?;
+            let normalized_pos: Vec<NormalizedPos> =
+                d.read_struct_field("normalized_pos", 9, |d| Decodable::decode(d))?;
             Ok(SourceFile {
                 name,
                 name_was_remapped,
@@ -1050,6 +1066,7 @@ impl Decodable for SourceFile {
                 lines,
                 multibyte_chars,
                 non_narrow_chars,
+                normalized_pos,
                 name_hash,
             })
         })
@@ -1068,8 +1085,7 @@ impl SourceFile {
                unmapped_path: FileName,
                mut src: String,
                start_pos: BytePos) -> Result<SourceFile, OffsetOverflowError> {
-        remove_bom(&mut src);
-        normalize_newlines(&mut src);
+        let normalized_pos = normalize_src(&mut src, start_pos);
 
         let src_hash = {
             let mut hasher: StableHasher = StableHasher::new();
@@ -1102,6 +1118,7 @@ impl SourceFile {
             lines,
             multibyte_chars,
             non_narrow_chars,
+            normalized_pos,
             name_hash,
         })
     }
@@ -1228,12 +1245,44 @@ impl SourceFile {
     pub fn contains(&self, byte_pos: BytePos) -> bool {
         byte_pos >= self.start_pos && byte_pos <= self.end_pos
     }
+
+    /// Calculates the original byte position relative to the start of the file
+    /// based on the given byte position.
+    pub fn original_relative_byte_pos(&self, pos: BytePos) -> BytePos {
+
+        // Diff before any records is 0. Otherwise use the previously recorded
+        // diff as that applies to the following characters until a new diff
+        // is recorded.
+        let diff = match self.normalized_pos.binary_search_by(
+                            |np| np.pos.cmp(&pos)) {
+            Ok(i) => self.normalized_pos[i].diff,
+            Err(i) if i == 0 => 0,
+            Err(i) => self.normalized_pos[i-1].diff,
+        };
+
+        BytePos::from_u32(pos.0 - self.start_pos.0 + diff)
+    }
+}
+
+/// Normalizes the source code and records the normalizations.
+fn normalize_src(src: &mut String, start_pos: BytePos) -> Vec<NormalizedPos> {
+    let mut normalized_pos = vec![];
+    remove_bom(src, &mut normalized_pos);
+    normalize_newlines(src, &mut normalized_pos);
+
+    // Offset all the positions by start_pos to match the final file positions.
+    for np in &mut normalized_pos {
+        np.pos.0 += start_pos.0;
+    }
+
+    normalized_pos
 }
 
 /// Removes UTF-8 BOM, if any.
-fn remove_bom(src: &mut String) {
+fn remove_bom(src: &mut String, normalized_pos: &mut Vec<NormalizedPos>) {
     if src.starts_with("\u{feff}") {
         src.drain(..3);
+        normalized_pos.push(NormalizedPos { pos: BytePos(0), diff: 3 });
     }
 }
 
@@ -1241,7 +1290,7 @@ fn remove_bom(src: &mut String) {
 /// Replaces `\r\n` with `\n` in-place in `src`.
 ///
 /// Returns error if there's a lone `\r` in the string
-fn normalize_newlines(src: &mut String) {
+fn normalize_newlines(src: &mut String, normalized_pos: &mut Vec<NormalizedPos>) {
     if !src.as_bytes().contains(&b'\r') {
         return;
     }
@@ -1254,6 +1303,8 @@ fn normalize_newlines(src: &mut String) {
     let mut buf = std::mem::replace(src, String::new()).into_bytes();
     let mut gap_len = 0;
     let mut tail = buf.as_mut_slice();
+    let mut cursor = 0;
+    let original_gap = normalized_pos.last().map_or(0, |l| l.diff);
     loop {
         let idx = match find_crlf(&tail[gap_len..]) {
             None => tail.len(),
@@ -1264,7 +1315,12 @@ fn normalize_newlines(src: &mut String) {
         if tail.len() == gap_len {
             break;
         }
+        cursor += idx - gap_len;
         gap_len += 1;
+        normalized_pos.push(NormalizedPos {
+            pos: BytePos::from_usize(cursor + 1),
+            diff: original_gap + gap_len as u32,
+        });
     }
 
     // Account for removed `\r`.

src/libsyntax_pos/tests.rs

@@ -19,20 +19,25 @@ fn test_lookup_line() {
 
 #[test]
 fn test_normalize_newlines() {
-    fn check(before: &str, after: &str) {
+    fn check(before: &str, after: &str, expected_positions: &[u32]) {
         let mut actual = before.to_string();
-        normalize_newlines(&mut actual);
+        let mut actual_positions = vec![];
+        normalize_newlines(&mut actual, &mut actual_positions);
+        let actual_positions : Vec<_> = actual_positions
+            .into_iter()
+            .map(|nc| nc.pos.0).collect();
         assert_eq!(actual.as_str(), after);
+        assert_eq!(actual_positions, expected_positions);
     }
-    check("", "");
-    check("\n", "\n");
-    check("\r", "\r");
-    check("\r\r", "\r\r");
-    check("\r\n", "\n");
-    check("hello world", "hello world");
-    check("hello\nworld", "hello\nworld");
-    check("hello\r\nworld", "hello\nworld");
-    check("\r\nhello\r\nworld\r\n", "\nhello\nworld\n");
-    check("\r\r\n", "\r\n");
-    check("hello\rworld", "hello\rworld");
+    check("", "", &[]);
+    check("\n", "\n", &[]);
+    check("\r", "\r", &[]);
+    check("\r\r", "\r\r", &[]);
+    check("\r\n", "\n", &[1]);
+    check("hello world", "hello world", &[]);
+    check("hello\nworld", "hello\nworld", &[]);
+    check("hello\r\nworld", "hello\nworld", &[6]);
+    check("\r\nhello\r\nworld\r\n", "\nhello\nworld\n", &[1, 7, 13]);
+    check("\r\r\n", "\r\n", &[2]);
+    check("hello\rworld", "hello\rworld", &[]);
 }

src/test/ui/.gitattributes

@@ -1,3 +1,6 @@
 lexer-crlf-line-endings-string-literal-doc-comment.rs -text
+json-bom-plus-crlf.rs -text
+json-bom-plus-crlf-multifile.rs -text
+json-bom-plus-crlf-multifile-aux.rs -text
 trailing-carriage-return-in-string.rs -text
 *.bin -text

src/test/ui/json-bom-plus-crlf-multifile-aux.rs

@@ -0,0 +1,27 @@
+// (This line has BOM so it's ignored by compiletest for directives)
+//
+// ignore-test Not a test. Used by other tests
+// ignore-tidy-cr
+
+// For easier verifying, the byte offsets in this file should match those
+// in the json-bom-plus-crlf.rs - given the actual fn is identical (just with
+// a different, but equally sized name), the easiest way to do this is to
+// ensure the two files are of equal size on disk.
+// Padding............................
+
+// N.B., this file needs CRLF line endings. The .gitattributes file in
+// this directory should enforce it.
+
+pub fn test() {
+
+    let s : String = 1;  // Error in the middle of line.
+
+    let s : String = 1
+    ;  // Error before the newline.
+
+    let s : String =
+1;  // Error after the newline.
+
+    let s : String = (
+    );  // Error spanning the newline.
+}

src/test/ui/json-bom-plus-crlf-multifile.rs

@@ -0,0 +1,12 @@
+// (This line has BOM so it's ignored by compiletest for directives)
+//
+// build-fail
+// compile-flags: --json=diagnostic-short --error-format=json
+// ignore-tidy-cr
+
+#[path = "json-bom-plus-crlf-multifile-aux.rs"]
+mod json_bom_plus_crlf_multifile_aux;
+
+fn main() {
+    json_bom_plus_crlf_multifile_aux::test();
+}

src/test/ui/json-bom-plus-crlf-multifile.stderr

@@ -0,0 +1,86 @@
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:17:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:19:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:23:1: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf-multifile-aux.rs","byte_start":801,"byte_end":809,"line_start":25,"line_end":26,"column_start":22,"column_end":6,"is_primary":true,"text":[{"text":"    let s : String = (","highlight_start":22,"highlight_end":23},{"text":"    );  // Error spanning the newline.","highlight_start":1,"highlight_end":6}],"label":"expected struct `std::string::String`, found ()","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `()`","code":null,"level":"note","spans":[],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf-multifile-aux.rs:25:22: error[E0308]: mismatched types
+"}
+{"message":"aborting due to 4 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 4 previous errors
+"}

src/test/ui/json-bom-plus-crlf.rs

@@ -0,0 +1,27 @@
+// (This line has BOM so it's ignored by compiletest for directives)
+//
+// build-fail
+// compile-flags: --json=diagnostic-short --error-format=json
+// ignore-tidy-cr
+
+// For easier verifying, the byte offsets in this file should match those
+// in the json_bom_plus_crlf_multifile_aux.rs - given the actual fn is
+// identical (just with a different, but equally sized name), the easiest way
+// to do this is to ensure the two files are of equal size on disk.
+
+// N.B., this file needs CRLF line endings. The .gitattributes file in
+// this directory should enforce it.
+
+fn main() {
+
+    let s : String = 1;  // Error in the middle of line.
+
+    let s : String = 1
+    ;  // Error before the newline.
+
+    let s : String =
+1;  // Error after the newline.
+
+    let s : String = (
+    );  // Error spanning the newline.
+}

src/test/ui/json-bom-plus-crlf.stderr

@@ -0,0 +1,86 @@
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":621,"byte_end":622,"line_start":17,"line_end":17,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1;  // Error in the middle of line.","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:17:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":681,"byte_end":682,"line_start":19,"line_end":19,"column_start":22,"column_end":23,"is_primary":true,"text":[{"text":"    let s : String = 1","highlight_start":22,"highlight_end":23}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:19:22: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":"expected struct `std::string::String`, found integer","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `{integer}`","code":null,"level":"note","spans":[],"children":[],"rendered":null},{"message":"try using a conversion method","code":null,"level":"help","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":745,"byte_end":746,"line_start":23,"line_end":23,"column_start":1,"column_end":2,"is_primary":true,"text":[{"text":"1;  // Error after the newline.","highlight_start":1,"highlight_end":2}],"label":null,"suggested_replacement":"1.to_string()","suggestion_applicability":"MaybeIncorrect","expansion":null}],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:23:1: error[E0308]: mismatched types
+"}
+{"message":"mismatched types","code":{"code":"E0308","explanation":"
+This error occurs when the compiler was unable to infer the concrete type of a
+variable. It can occur for several cases, the most common of which is a
+mismatch in the expected type that the compiler inferred for a variable's
+initializing expression, and the actual type explicitly assigned to the
+variable.
+
+For example:
+
+```compile_fail,E0308
+let x: i32 = \"I am not a number!\";
+//     ~~~   ~~~~~~~~~~~~~~~~~~~~
+//      |             |
+//      |    initializing expression;
+//      |    compiler infers type `&str`
+//      |
+//    type `i32` assigned to variable `x`
+```
+"},"level":"error","spans":[{"file_name":"$DIR/json-bom-plus-crlf.rs","byte_start":801,"byte_end":809,"line_start":25,"line_end":26,"column_start":22,"column_end":6,"is_primary":true,"text":[{"text":"    let s : String = (","highlight_start":22,"highlight_end":23},{"text":"    );  // Error spanning the newline.","highlight_start":1,"highlight_end":6}],"label":"expected struct `std::string::String`, found ()","suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[{"message":"expected type `std::string::String`
+   found type `()`","code":null,"level":"note","spans":[],"children":[],"rendered":null}],"rendered":"$DIR/json-bom-plus-crlf.rs:25:22: error[E0308]: mismatched types
+"}
+{"message":"aborting due to 4 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to 4 previous errors
+"}