Rollup merge of #34403 - jonathandturner:move_liberror, r=alexcrichton

This PR refactors the 'errors' part of libsyntax into its own crate (librustc_errors).  This is the first part of a few refactorings to simplify error reporting and potentially support more output formats (like a standardized JSON output and possibly an --explain mode that can work with the user's code), though this PR stands on its own and doesn't assume further changes.

As part of separating out the errors crate, I have also refactored the code position portion of codemap into its own crate (libsyntax_pos).  While it's helpful to have the common code positions in a separate crate for the new errors crate, this may also enable further simplifications in the future.

7 files changed, 54 insertions, 45 deletions

diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index db643eb0df0..f6e94b7caea 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -10,7 +10,8 @@
 
 use attr;
 use ast;
-use codemap::{spanned, Spanned, mk_sp, Span};
+use syntax_pos::{mk_sp, Span};
+use codemap::{spanned, Spanned};
 use parse::common::SeqSep;
 use parse::PResult;
 use parse::token;
diff --git a/src/libsyntax/parse/lexer/comments.rs b/src/libsyntax/parse/lexer/comments.rs
index 06d255d5c0f..5eb5605ea71 100644
--- a/src/libsyntax/parse/lexer/comments.rs
+++ b/src/libsyntax/parse/lexer/comments.rs
@@ -11,7 +11,8 @@
 pub use self::CommentStyle::*;
 
 use ast;
-use codemap::{BytePos, CharPos, CodeMap, Pos};
+use codemap::CodeMap;
+use syntax_pos::{BytePos, CharPos, Pos};
 use errors;
 use parse::lexer::is_block_doc_comment;
 use parse::lexer::{StringReader, TokenAndSpan};
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index d78a81dec83..809f4daa361 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -9,8 +9,8 @@
 // except according to those terms.
 
 use ast;
-use codemap::{BytePos, CharPos, CodeMap, Pos, Span};
-use codemap;
+use syntax_pos::{self, BytePos, CharPos, Pos, Span};
+use codemap::CodeMap;
 use errors::{FatalError, Handler, DiagnosticBuilder};
 use ext::tt::transcribe::tt_next_token;
 use parse::token::{self, keywords, str_to_ident};
@@ -84,7 +84,7 @@ pub struct StringReader<'a> {
     pub col: CharPos,
     /// The last character to be read
     pub curr: Option<char>,
-    pub filemap: Rc<codemap::FileMap>,
+    pub filemap: Rc<syntax_pos::FileMap>,
     // cached:
     pub peek_tok: token::Token,
     pub peek_span: Span,
@@ -162,7 +162,7 @@ impl<'a> Reader for TtReader<'a> {
 impl<'a> StringReader<'a> {
     /// For comments.rs, which hackily pokes into pos and curr
     pub fn new_raw<'b>(span_diagnostic: &'b Handler,
-                       filemap: Rc<codemap::FileMap>)
+                       filemap: Rc<syntax_pos::FileMap>)
                        -> StringReader<'b> {
         if filemap.src.is_none() {
             span_diagnostic.bug(&format!("Cannot lex filemap \
@@ -181,7 +181,7 @@ impl<'a> StringReader<'a> {
             filemap: filemap,
             // dummy values; not read
             peek_tok: token::Eof,
-            peek_span: codemap::DUMMY_SP,
+            peek_span: syntax_pos::DUMMY_SP,
             source_text: source_text,
             fatal_errs: Vec::new(),
         };
@@ -190,7 +190,7 @@ impl<'a> StringReader<'a> {
     }
 
     pub fn new<'b>(span_diagnostic: &'b Handler,
-                   filemap: Rc<codemap::FileMap>)
+                   filemap: Rc<syntax_pos::FileMap>)
                    -> StringReader<'b> {
         let mut sr = StringReader::new_raw(span_diagnostic, filemap);
         if let Err(_) = sr.advance_token() {
@@ -217,12 +217,12 @@ impl<'a> StringReader<'a> {
 
     /// Report a fatal error spanning [`from_pos`, `to_pos`).
     fn fatal_span_(&self, from_pos: BytePos, to_pos: BytePos, m: &str) -> FatalError {
-        self.fatal_span(codemap::mk_sp(from_pos, to_pos), m)
+        self.fatal_span(syntax_pos::mk_sp(from_pos, to_pos), m)
     }
 
     /// Report a lexical error spanning [`from_pos`, `to_pos`).
     fn err_span_(&self, from_pos: BytePos, to_pos: BytePos, m: &str) {
-        self.err_span(codemap::mk_sp(from_pos, to_pos), m)
+        self.err_span(syntax_pos::mk_sp(from_pos, to_pos), m)
     }
 
     /// Report a lexical error spanning [`from_pos`, `to_pos`), appending an
@@ -246,7 +246,7 @@ impl<'a> StringReader<'a> {
         for c in c.escape_default() {
             m.push(c)
         }
-        self.span_diagnostic.struct_span_fatal(codemap::mk_sp(from_pos, to_pos), &m[..])
+        self.span_diagnostic.struct_span_fatal(syntax_pos::mk_sp(from_pos, to_pos), &m[..])
     }
 
     /// Report a lexical error spanning [`from_pos`, `to_pos`), appending an
@@ -270,7 +270,7 @@ impl<'a> StringReader<'a> {
         for c in c.escape_default() {
             m.push(c)
         }
-        self.span_diagnostic.struct_span_err(codemap::mk_sp(from_pos, to_pos), &m[..])
+        self.span_diagnostic.struct_span_err(syntax_pos::mk_sp(from_pos, to_pos), &m[..])
     }
 
     /// Report a lexical error spanning [`from_pos`, `to_pos`), appending the
@@ -294,11 +294,11 @@ impl<'a> StringReader<'a> {
             None => {
                 if self.is_eof() {
                     self.peek_tok = token::Eof;
-                    self.peek_span = codemap::mk_sp(self.filemap.end_pos, self.filemap.end_pos);
+                    self.peek_span = syntax_pos::mk_sp(self.filemap.end_pos, self.filemap.end_pos);
                 } else {
                     let start_bytepos = self.last_pos;
                     self.peek_tok = self.next_token_inner()?;
-                    self.peek_span = codemap::mk_sp(start_bytepos, self.last_pos);
+                    self.peek_span = syntax_pos::mk_sp(start_bytepos, self.last_pos);
                 };
             }
         }
@@ -473,7 +473,7 @@ impl<'a> StringReader<'a> {
         match self.curr {
             Some(c) => {
                 if c.is_whitespace() {
-                    self.span_diagnostic.span_err(codemap::mk_sp(self.last_pos, self.last_pos),
+                    self.span_diagnostic.span_err(syntax_pos::mk_sp(self.last_pos, self.last_pos),
                                                   "called consume_any_line_comment, but there \
                                                    was whitespace");
                 }
@@ -524,13 +524,13 @@ impl<'a> StringReader<'a> {
 
                             Some(TokenAndSpan {
                                 tok: tok,
-                                sp: codemap::mk_sp(start_bpos, self.last_pos),
+                                sp: syntax_pos::mk_sp(start_bpos, self.last_pos),
                             })
                         })
                     } else {
                         Some(TokenAndSpan {
                             tok: token::Comment,
-                            sp: codemap::mk_sp(start_bpos, self.last_pos),
+                            sp: syntax_pos::mk_sp(start_bpos, self.last_pos),
                         })
                     };
                 }
@@ -563,7 +563,7 @@ impl<'a> StringReader<'a> {
                     }
                     return Some(TokenAndSpan {
                         tok: token::Shebang(self.name_from(start)),
-                        sp: codemap::mk_sp(start, self.last_pos),
+                        sp: syntax_pos::mk_sp(start, self.last_pos),
                     });
                 }
             }
@@ -591,7 +591,7 @@ impl<'a> StringReader<'a> {
                 }
                 let c = Some(TokenAndSpan {
                     tok: token::Whitespace,
-                    sp: codemap::mk_sp(start_bpos, self.last_pos),
+                    sp: syntax_pos::mk_sp(start_bpos, self.last_pos),
                 });
                 debug!("scanning whitespace: {:?}", c);
                 c
@@ -653,7 +653,7 @@ impl<'a> StringReader<'a> {
 
             Some(TokenAndSpan {
                 tok: tok,
-                sp: codemap::mk_sp(start_bpos, self.last_pos),
+                sp: syntax_pos::mk_sp(start_bpos, self.last_pos),
             })
         })
     }
@@ -850,7 +850,7 @@ impl<'a> StringReader<'a> {
                                 let valid = if self.curr_is('{') {
                                     self.scan_unicode_escape(delim) && !ascii_only
                                 } else {
-                                    let span = codemap::mk_sp(start, self.last_pos);
+                                    let span = syntax_pos::mk_sp(start, self.last_pos);
                                     self.span_diagnostic
                                         .struct_span_err(span, "incorrect unicode escape sequence")
                                         .span_help(span,
@@ -888,13 +888,13 @@ impl<'a> StringReader<'a> {
                                                                         },
                                                                         c);
                                 if e == '\r' {
-                                    err.span_help(codemap::mk_sp(escaped_pos, last_pos),
+                                    err.span_help(syntax_pos::mk_sp(escaped_pos, last_pos),
                                                   "this is an isolated carriage return; consider \
                                                    checking your editor and version control \
                                                    settings");
                                 }
                                 if (e == '{' || e == '}') && !ascii_only {
-                                    err.span_help(codemap::mk_sp(escaped_pos, last_pos),
+                                    err.span_help(syntax_pos::mk_sp(escaped_pos, last_pos),
                                                   "if used in a formatting string, curly braces \
                                                    are escaped with `{{` and `}}`");
                                 }
@@ -1677,7 +1677,8 @@ fn ident_continue(c: Option<char>) -> bool {
 mod tests {
     use super::*;
 
-    use codemap::{BytePos, CodeMap, Span, NO_EXPANSION};
+    use syntax_pos::{BytePos, Span, NO_EXPANSION};
+    use codemap::CodeMap;
     use errors;
     use parse::token;
     use parse::token::str_to_ident;
@@ -1686,7 +1687,10 @@ mod tests {
 
     fn mk_sh(cm: Rc<CodeMap>) -> errors::Handler {
         // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
-        let emitter = errors::emitter::EmitterWriter::new(Box::new(io::sink()), None, cm);
+        let emitter = errors::emitter::EmitterWriter::new(Box::new(io::sink()),
+                                                None,
+                                                cm,
+                                                errors::snippet::FormatMode::EnvironmentSelected);
         errors::Handler::with_emitter(true, false, Box::new(emitter))
     }
 
@@ -1889,7 +1893,7 @@ mod tests {
         let mut lexer = setup(&cm, &sh, "// test\r\n/// test\r\n".to_string());
         let comment = lexer.next_token();
         assert_eq!(comment.tok, token::Comment);
-        assert_eq!(comment.sp, ::codemap::mk_sp(BytePos(0), BytePos(7)));
+        assert_eq!(comment.sp, ::syntax_pos::mk_sp(BytePos(0), BytePos(7)));
         assert_eq!(lexer.next_token().tok, token::Whitespace);
         assert_eq!(lexer.next_token().tok,
                    token::DocComment(token::intern("/// test")));
diff --git a/src/libsyntax/parse/lexer/unicode_chars.rs b/src/libsyntax/parse/lexer/unicode_chars.rs
index d337c78bee8..dab97d1d5a6 100644
--- a/src/libsyntax/parse/lexer/unicode_chars.rs
+++ b/src/libsyntax/parse/lexer/unicode_chars.rs
@@ -11,7 +11,7 @@
 // Characters and their corresponding confusables were collected from
 // http://www.unicode.org/Public/security/revision-06/confusables.txt
 
-use codemap::mk_sp as make_span;
+use syntax_pos::mk_sp as make_span;
 use errors::DiagnosticBuilder;
 use super::StringReader;
 
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index 2e4d46bc983..0796f298be1 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -11,7 +11,8 @@
 //! The main parser interface
 
 use ast;
-use codemap::{self, Span, CodeMap, FileMap};
+use codemap::CodeMap;
+use syntax_pos::{self, Span, FileMap};
 use errors::{Handler, ColorConfig, DiagnosticBuilder};
 use parse::parser::Parser;
 use parse::token::InternedString;
@@ -211,8 +212,8 @@ pub fn filemap_to_parser<'a>(sess: &'a ParseSess,
     let end_pos = filemap.end_pos;
     let mut parser = tts_to_parser(sess, filemap_to_tts(sess, filemap), cfg);
 
-    if parser.token == token::Eof && parser.span == codemap::DUMMY_SP {
-        parser.span = codemap::mk_sp(end_pos, end_pos);
+    if parser.token == token::Eof && parser.span == syntax_pos::DUMMY_SP {
+        parser.span = syntax_pos::mk_sp(end_pos, end_pos);
     }
 
     parser
@@ -661,7 +662,8 @@ pub fn integer_lit(s: &str,
 mod tests {
     use super::*;
     use std::rc::Rc;
-    use codemap::{Span, BytePos, Pos, Spanned, NO_EXPANSION};
+    use syntax_pos::{Span, BytePos, Pos, NO_EXPANSION};
+    use codemap::Spanned;
     use ast::{self, TokenTree, PatKind};
     use abi::Abi;
     use attr::{first_attr_value_str_by_name, AttrMetaMethods};
@@ -673,7 +675,7 @@ mod tests {
     use util::parser_testing::{string_to_tts, string_to_parser};
     use util::parser_testing::{string_to_expr, string_to_item, string_to_stmt};
 
-    // produce a codemap::span
+    // produce a syntax_pos::span
     fn sp(a: u32, b: u32) -> Span {
         Span {lo: BytePos(a), hi: BytePos(b), expn_id: NO_EXPANSION}
     }
diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index 75f1ac49c9a..a1d7ddcdf4b 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -13,7 +13,7 @@
 //!
 //! Obsolete syntax that becomes too hard to parse can be removed.
 
-use codemap::Span;
+use syntax_pos::Span;
 use parse::parser;
 
 /// The specific types of unsupported syntax
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index de41ab5e189..99eddce3645 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -40,7 +40,8 @@ use ast::{Visibility, WhereClause};
 use attr::{ThinAttributes, ThinAttributesExt, AttributesExt};
 use ast::{BinOpKind, UnOp};
 use ast;
-use codemap::{self, Span, BytePos, Spanned, spanned, mk_sp, CodeMap};
+use codemap::{self, CodeMap, Spanned, spanned};
+use syntax_pos::{self, Span, BytePos, mk_sp};
 use errors::{self, DiagnosticBuilder};
 use ext::tt::macro_parser;
 use parse;
@@ -344,7 +345,7 @@ impl<'a> Parser<'a> {
     {
         let tok0 = rdr.real_token();
         let span = tok0.sp;
-        let filename = if span != codemap::DUMMY_SP {
+        let filename = if span != syntax_pos::DUMMY_SP {
             Some(sess.codemap().span_to_filename(span))
         } else { None };
         let placeholder = TokenAndSpan {
@@ -3525,7 +3526,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parse the fields of a struct-like pattern
-    fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<codemap::Spanned<ast::FieldPat>> , bool)> {
+    fn parse_pat_fields(&mut self) -> PResult<'a, (Vec<codemap::Spanned<ast::FieldPat>>, bool)> {
         let mut fields = Vec::new();
         let mut etc = false;
         let mut first = true;
@@ -3595,9 +3596,9 @@ impl<'a> Parser<'a> {
             };
 
             fields.push(codemap::Spanned { span: mk_sp(lo, hi),
-                                           node: ast::FieldPat { ident: fieldname,
-                                                                 pat: subpat,
-                                                                 is_shorthand: is_shorthand }});
+                                              node: ast::FieldPat { ident: fieldname,
+                                                                    pat: subpat,
+                                                                    is_shorthand: is_shorthand }});
         }
         return Ok((fields, etc));
     }
@@ -3688,7 +3689,7 @@ impl<'a> Parser<'a> {
                             SeqSep::none(), |p| p.parse_token_tree())?;
                         let mac = Mac_ { path: path, tts: tts, ctxt: EMPTY_CTXT };
                         pat = PatKind::Mac(codemap::Spanned {node: mac,
-                                                       span: mk_sp(lo, self.last_span.hi)});
+                                                               span: mk_sp(lo, self.last_span.hi)});
                     } else {
                         // Parse ident @ pat
                         // This can give false positives and parse nullary enums,
@@ -4935,8 +4936,8 @@ impl<'a> Parser<'a> {
                                             |p| p.parse_token_tree())?;
             let m_ = Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT };
             let m: ast::Mac = codemap::Spanned { node: m_,
-                                                span: mk_sp(lo,
-                                                            self.last_span.hi) };
+                                                    span: mk_sp(lo,
+                                                                self.last_span.hi) };
             if delim != token::Brace {
                 self.expect(&token::Semi)?
             }
@@ -5274,7 +5275,7 @@ impl<'a> Parser<'a> {
             return Err(self.fatal(&format!("expected item, found `{}`", token_str)));
         }
 
-        let hi = if self.span == codemap::DUMMY_SP {
+        let hi = if self.span == syntax_pos::DUMMY_SP {
             inner_lo
         } else {
             self.last_span.hi
@@ -6020,8 +6021,8 @@ impl<'a> Parser<'a> {
             // single-variant-enum... :
             let m = Mac_ { path: pth, tts: tts, ctxt: EMPTY_CTXT };
             let m: ast::Mac = codemap::Spanned { node: m,
-                                             span: mk_sp(mac_lo,
-                                                         self.last_span.hi) };
+                                                 span: mk_sp(mac_lo,
+                                                             self.last_span.hi) };
 
             if delim != token::Brace {
                 if !self.eat(&token::Semi) {