Merge pull request #32795 from pnkfelix/parser-backports-for-beta

Parser backports for beta

Author: nikomatsakis

src/librustc/session/config.rs

@@ -138,6 +138,7 @@ pub struct Options {
     pub no_trans: bool,
     pub error_format: ErrorOutputType,
     pub treat_err_as_bug: bool,
+    pub continue_parse_after_error: bool,
     pub mir_opt_level: usize,
 
     /// if true, build up the dep-graph
@@ -255,6 +256,7 @@ pub fn basic_options() -> Options {
         parse_only: false,
         no_trans: false,
         treat_err_as_bug: false,
+        continue_parse_after_error: false,
         mir_opt_level: 1,
         build_dep_graph: false,
         dump_dep_graph: false,
@@ -629,6 +631,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "run all passes except translation; no output"),
     treat_err_as_bug: bool = (false, parse_bool,
           "treat all errors that occur as bugs"),
+    continue_parse_after_error: bool = (false, parse_bool,
+          "attempt to recover from parse errors (experimental)"),
     incr_comp: bool = (false, parse_bool,
           "enable incremental compilation (experimental)"),
     dump_dep_graph: bool = (false, parse_bool,
@@ -1039,6 +1043,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
     let parse_only = debugging_opts.parse_only;
     let no_trans = debugging_opts.no_trans;
     let treat_err_as_bug = debugging_opts.treat_err_as_bug;
+    let continue_parse_after_error = debugging_opts.continue_parse_after_error;
     let mir_opt_level = debugging_opts.mir_opt_level.unwrap_or(1);
     let incremental_compilation = debugging_opts.incr_comp;
     let dump_dep_graph = debugging_opts.dump_dep_graph;
@@ -1218,6 +1223,7 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         parse_only: parse_only,
         no_trans: no_trans,
         treat_err_as_bug: treat_err_as_bug,
+        continue_parse_after_error: continue_parse_after_error,
         mir_opt_level: mir_opt_level,
         build_dep_graph: incremental_compilation || dump_dep_graph,
         dump_dep_graph: dump_dep_graph,

src/librustc_driver/driver.rs

@@ -421,6 +421,8 @@ pub fn phase_1_parse_input(sess: &Session, cfg: ast::CrateConfig, input: &Input)
     // memory, but they do not restore the initial state.
     syntax::ext::mtwt::reset_tables();
     token::reset_ident_interner();
+    let continue_after_error = sess.opts.continue_parse_after_error;
+    sess.diagnostic().set_continue_after_error(continue_after_error);
 
     let krate = time(sess.time_passes(), "parsing", || {
         match *input {
@@ -436,6 +438,8 @@ pub fn phase_1_parse_input(sess: &Session, cfg: ast::CrateConfig, input: &Input)
         }
     });
 
+    sess.diagnostic().set_continue_after_error(true);
+
     if sess.opts.debugging_opts.ast_json_noexpand {
         println!("{}", json::as_json(&krate));
     }

src/libsyntax/errors/mod.rs

@@ -370,6 +370,7 @@ pub struct Handler {
     emit: RefCell<Box<Emitter>>,
     pub can_emit_warnings: bool,
     treat_err_as_bug: bool,
+    continue_after_error: Cell<bool>,
     delayed_span_bug: RefCell<Option<(MultiSpan, String)>>,
 }
 
@@ -392,10 +393,15 @@ impl Handler {
             emit: RefCell::new(e),
             can_emit_warnings: can_emit_warnings,
             treat_err_as_bug: treat_err_as_bug,
+            continue_after_error: Cell::new(true),
             delayed_span_bug: RefCell::new(None),
         }
     }
 
+    pub fn set_continue_after_error(&self, continue_after_error: bool) {
+        self.continue_after_error.set(continue_after_error);
+    }
+
     pub fn struct_dummy<'a>(&'a self) -> DiagnosticBuilder<'a> {
         DiagnosticBuilder::new(&self.emit, Level::Cancelled, "")
     }
@@ -612,6 +618,7 @@ impl Handler {
                 lvl: Level) {
         if lvl == Warning && !self.can_emit_warnings { return }
         self.emit.borrow_mut().emit(msp, msg, None, lvl);
+        if !self.continue_after_error.get() { self.abort_if_errors(); }
     }
     pub fn emit_with_code(&self,
                           msp: Option<&MultiSpan>,
@@ -620,10 +627,12 @@ impl Handler {
                           lvl: Level) {
         if lvl == Warning && !self.can_emit_warnings { return }
         self.emit.borrow_mut().emit(msp, msg, Some(code), lvl);
+        if !self.continue_after_error.get() { self.abort_if_errors(); }
     }
     pub fn custom_emit(&self, rsp: RenderSpan, msg: &str, lvl: Level) {
         if lvl == Warning && !self.can_emit_warnings { return }
         self.emit.borrow_mut().custom_emit(&rsp, msg, lvl);
+        if !self.continue_after_error.get() { self.abort_if_errors(); }
     }
 }
 

src/libsyntax/parse/parser.rs

@@ -261,6 +261,7 @@ pub struct Parser<'a> {
     /// the previous token or None (only stashed sometimes).
     pub last_token: Option<Box<token::Token>>,
     last_token_interpolated: bool,
+    last_token_eof: bool,
     pub buffer: [TokenAndSpan; 4],
     pub buffer_start: isize,
     pub buffer_end: isize,
@@ -369,6 +370,7 @@ impl<'a> Parser<'a> {
             last_span: span,
             last_token: None,
             last_token_interpolated: false,
+            last_token_eof: false,
             buffer: [
                 placeholder.clone(),
                 placeholder.clone(),
@@ -939,7 +941,9 @@ impl<'a> Parser<'a> {
     {
         try!(self.expect(bra));
         let result = self.parse_seq_to_before_end(ket, sep, f);
-        self.bump();
+        if self.token == *ket {
+            self.bump();
+        }
         Ok(result)
     }
 
@@ -982,6 +986,15 @@ impl<'a> Parser<'a> {
 
     /// Advance the parser by one token
     pub fn bump(&mut self) {
+        if self.last_token_eof {
+            // Bumping after EOF is a bad sign, usually an infinite loop.
+            self.bug("attempted to bump the parser past EOF (may be stuck in a loop)");
+        }
+
+        if self.token == token::Eof {
+            self.last_token_eof = true;
+        }
+
         self.last_span = self.span;
         // Stash token for error recovery (sometimes; clone is not necessarily cheap).
         self.last_token = if self.token.is_ident() ||
@@ -1265,15 +1278,21 @@ impl<'a> Parser<'a> {
                     Ok(cua) => cua,
                     Err(e) => {
                         loop {
-                            p.bump();
-                            if p.token == token::Semi {
-                                p.bump();
-                                break;
-                            }
+                            match p.token {
+                                token::Eof => break,
 
-                            if p.token == token::OpenDelim(token::DelimToken::Brace) {
-                                try!(p.parse_token_tree());
-                                break;
+                                token::CloseDelim(token::Brace) |
+                                token::Semi => {
+                                    p.bump();
+                                    break;
+                                }
+
+                                token::OpenDelim(token::Brace) => {
+                                    try!(p.parse_token_tree());
+                                    break;
+                                }
+
+                                _ => p.bump()
                             }
                         }
 
@@ -3790,7 +3809,9 @@ impl<'a> Parser<'a> {
     fn recover_stmt_(&mut self, break_on_semi: SemiColonMode) {
         let mut brace_depth = 0;
         let mut bracket_depth = 0;
+        debug!("recover_stmt_ enter loop");
         loop {
+            debug!("recover_stmt_ loop {:?}", self.token);
             match self.token {
                 token::OpenDelim(token::DelimToken::Brace) => {
                     brace_depth += 1;
@@ -3802,6 +3823,7 @@ impl<'a> Parser<'a> {
                 }
                 token::CloseDelim(token::DelimToken::Brace) => {
                     if brace_depth == 0 {
+                        debug!("recover_stmt_ return - close delim {:?}", self.token);
                         return;
                     }
                     brace_depth -= 1;
@@ -3814,12 +3836,16 @@ impl<'a> Parser<'a> {
                     }
                     self.bump();
                 }
-                token::Eof => return,
+                token::Eof => {
+                    debug!("recover_stmt_ return - Eof");
+                    return;
+                }
                 token::Semi => {
                     self.bump();
                     if break_on_semi == SemiColonMode::Break &&
                        brace_depth == 0 &&
                        bracket_depth == 0 {
+                        debug!("recover_stmt_ return - Semi");
                         return;
                     }
                 }
@@ -4008,6 +4034,8 @@ impl<'a> Parser<'a> {
         while !self.eat(&token::CloseDelim(token::Brace)) {
             let Spanned {node, span} = if let Some(s) = self.parse_stmt_() {
                 s
+            } else if self.token == token::Eof {
+                break;
             } else {
                 // Found only `;` or `}`.
                 continue;

src/test/compile-fail/issue-12560-2.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 // For style and consistency reasons, non-parametrized enum variants must
 // be used simply as `ident` instead of `ident ()`.
 // This test-case covers enum matching.

src/test/compile-fail/issue-28433.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 enum bird {
     pub duck,
     //~^ ERROR: expected identifier, found keyword `pub`

src/test/compile-fail/issue-30715.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 macro_rules! parallel {
     (
         // If future has `pred`/`moelarry` fragments (where "pred" is

src/test/compile-fail/macro-incomplete-parse.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 macro_rules! ignored_item {
     () => {
         fn foo() {}

src/test/compile-fail/parse-error-correct.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 // Test that the parser is error correcting missing idents. Despite a parsing
 // error (or two), we still run type checking (and don't get extra errors there).
 

src/test/compile-fail/parser-recovery-1.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 // Test that we can recover from missing braces in the parser.
 
 trait Foo {

src/test/compile-fail/parser-recovery-2.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 // Test that we can recover from mismatched braces in the parser.
 
 trait Foo {

src/test/compile-fail/self_type_keyword.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z continue-parse-after-error
+
 struct Self;
 //~^ ERROR expected identifier, found keyword `Self`
 

src/test/parse-fail/ascii-only-character-escape.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 
 fn main() {
     let x = "\x80"; //~ ERROR may only be used

src/test/parse-fail/bad-char-literals.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 
 // ignore-tidy-cr
 // ignore-tidy-tab

src/test/parse-fail/bad-lit-suffixes.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 
 
 extern

src/test/parse-fail/byte-literals.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 
 
 // ignore-tidy-tab

src/test/parse-fail/byte-string-literals.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 
 
 // ignore-tidy-tab

src/test/parse-fail/issue-10412.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 
 
 trait Serializable<'self, T> { //~ ERROR no longer a special lifetime

src/test/parse-fail/issue-10636-2.rs

@@ -17,5 +17,4 @@ pub fn trace_option(option: Option<isize>) { //~ HELP did you mean to close this
     option.map(|some| 42; //~ NOTE: unclosed delimiter
                           //~^ ERROR: expected one of
 } //~ ERROR: incorrect close delimiter
-//~^ ERROR: expected one of
-//~ ERROR: this file contains an un-closed delimiter
+//~^ ERROR: unexpected token

src/test/parse-fail/issue-23620-invalid-escapes.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z parse-only -Z continue-parse-after-error
+
 fn main() {
     let _ = b"\u{a66e}";
     //~^ ERROR unicode escape sequences cannot be used as a byte or in a byte string

src/test/parse-fail/issue-32446.rs

@@ -0,0 +1,16 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags: -Z parse-only
+
+fn main() {}
+
+// This used to end up in an infite loop trying to bump past EOF.
+trait T { ... } //~ ERROR

src/test/parse-fail/lex-bad-binary-literal.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// compile-flags: -Z parse-only -Z continue-parse-after-error
+
 fn main() {
     0b121; //~ ERROR invalid digit for a base 2 literal
     0b10_10301; //~ ERROR invalid digit for a base 2 literal

src/test/parse-fail/lex-bad-char-literals-1.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// compile-flags: -Z parse-only -Z continue-parse-after-error
 static c3: char =
     '\x1' //~ ERROR: numeric character escape is too short
 ;