Rollup merge of rust-lang#108297 - chenyukang:yukang/delim-error-exit, r=petrochenkov

Exit when there are unmatched delims to avoid noisy diagnostics

From rust-lang#104012 (comment)
r? ``@petrochenkov``

Author: matthiaskrgr

compiler/rustc_expand/src/tests.rs

@@ -43,7 +43,6 @@ pub(crate) fn string_to_stream(source_str: String) -> TokenStream {
         ps.source_map().new_source_file(PathBuf::from("bogofile").into(), source_str),
         None,
     )
-    .0
 }
 
 /// Parses a string, returns a crate.

compiler/rustc_parse/src/lexer/diagnostics.rs

@@ -1,4 +1,4 @@
-use super::UnmatchedBrace;
+use super::UnmatchedDelim;
 use rustc_ast::token::Delimiter;
 use rustc_errors::Diagnostic;
 use rustc_span::source_map::SourceMap;
@@ -8,7 +8,7 @@ use rustc_span::Span;
 pub struct TokenTreeDiagInfo {
     /// Stack of open delimiters and their spans. Used for error message.
     pub open_braces: Vec<(Delimiter, Span)>,
-    pub unmatched_braces: Vec<UnmatchedBrace>,
+    pub unmatched_delims: Vec<UnmatchedDelim>,
 
     /// Used only for error recovery when arriving to EOF with mismatched braces.
     pub last_unclosed_found_span: Option<Span>,
@@ -32,10 +32,10 @@ pub fn same_identation_level(sm: &SourceMap, open_sp: Span, close_sp: Span) -> b
 // it's more friendly compared to report `unmatched error` in later phase
 pub fn report_missing_open_delim(
     err: &mut Diagnostic,
-    unmatched_braces: &[UnmatchedBrace],
+    unmatched_delims: &[UnmatchedDelim],
 ) -> bool {
     let mut reported_missing_open = false;
-    for unmatch_brace in unmatched_braces.iter() {
+    for unmatch_brace in unmatched_delims.iter() {
         if let Some(delim) = unmatch_brace.found_delim
             && matches!(delim, Delimiter::Parenthesis | Delimiter::Bracket)
         {
@@ -60,7 +60,7 @@ pub fn report_suspicious_mismatch_block(
     sm: &SourceMap,
     delim: Delimiter,
 ) {
-    if report_missing_open_delim(err, &diag_info.unmatched_braces) {
+    if report_missing_open_delim(err, &diag_info.unmatched_delims) {
         return;
     }
 

compiler/rustc_parse/src/lexer/mod.rs

@@ -1,10 +1,11 @@
 use crate::errors;
 use crate::lexer::unicode_chars::UNICODE_ARRAY;
+use crate::make_unclosed_delims_error;
 use rustc_ast::ast::{self, AttrStyle};
 use rustc_ast::token::{self, CommentKind, Delimiter, Token, TokenKind};
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::util::unicode::contains_text_flow_control_chars;
-use rustc_errors::{error_code, Applicability, DiagnosticBuilder, PResult, StashKey};
+use rustc_errors::{error_code, Applicability, Diagnostic, DiagnosticBuilder, StashKey};
 use rustc_lexer::unescape::{self, Mode};
 use rustc_lexer::Cursor;
 use rustc_lexer::{Base, DocStyle, RawStrError};
@@ -31,7 +32,7 @@ use unescape_error_reporting::{emit_unescape_error, escaped_char};
 rustc_data_structures::static_assert_size!(rustc_lexer::Token, 12);
 
 #[derive(Clone, Debug)]
-pub struct UnmatchedBrace {
+pub struct UnmatchedDelim {
     pub expected_delim: Delimiter,
     pub found_delim: Option<Delimiter>,
     pub found_span: Span,
@@ -44,7 +45,7 @@ pub(crate) fn parse_token_trees<'a>(
     mut src: &'a str,
     mut start_pos: BytePos,
     override_span: Option<Span>,
-) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
+) -> Result<TokenStream, Vec<Diagnostic>> {
     // Skip `#!`, if present.
     if let Some(shebang_len) = rustc_lexer::strip_shebang(src) {
         src = &src[shebang_len..];
@@ -61,7 +62,29 @@ pub(crate) fn parse_token_trees<'a>(
         override_span,
         nbsp_is_whitespace: false,
     };
-    tokentrees::TokenTreesReader::parse_all_token_trees(string_reader)
+    let (token_trees, unmatched_delims) =
+        tokentrees::TokenTreesReader::parse_all_token_trees(string_reader);
+    match token_trees {
+        Ok(stream) if unmatched_delims.is_empty() => Ok(stream),
+        _ => {
+            // Return error if there are unmatched delimiters or unclosng delimiters.
+            // We emit delimiter mismatch errors first, then emit the unclosing delimiter mismatch
+            // because the delimiter mismatch is more likely to be the root cause of error
+
+            let mut buffer = Vec::with_capacity(1);
+            // Not using `emit_unclosed_delims` to use `db.buffer`
+            for unmatched in unmatched_delims {
+                if let Some(err) = make_unclosed_delims_error(unmatched, &sess) {
+                    err.buffer(&mut buffer);
+                }
+            }
+            if let Err(err) = token_trees {
+                // Add unclosing delimiter error
+                err.buffer(&mut buffer);
+            }
+            Err(buffer)
+        }
+    }
 }
 
 struct StringReader<'a> {

compiler/rustc_parse/src/lexer/tokentrees.rs

@@ -1,7 +1,7 @@
 use super::diagnostics::report_suspicious_mismatch_block;
 use super::diagnostics::same_identation_level;
 use super::diagnostics::TokenTreeDiagInfo;
-use super::{StringReader, UnmatchedBrace};
+use super::{StringReader, UnmatchedDelim};
 use rustc_ast::token::{self, Delimiter, Token};
 use rustc_ast::tokenstream::{DelimSpan, Spacing, TokenStream, TokenTree};
 use rustc_ast_pretty::pprust::token_to_string;
@@ -18,14 +18,14 @@ pub(super) struct TokenTreesReader<'a> {
 impl<'a> TokenTreesReader<'a> {
     pub(super) fn parse_all_token_trees(
         string_reader: StringReader<'a>,
-    ) -> (PResult<'a, TokenStream>, Vec<UnmatchedBrace>) {
+    ) -> (PResult<'a, TokenStream>, Vec<UnmatchedDelim>) {
         let mut tt_reader = TokenTreesReader {
             string_reader,
             token: Token::dummy(),
             diag_info: TokenTreeDiagInfo::default(),
         };
         let res = tt_reader.parse_token_trees(/* is_delimited */ false);
-        (res, tt_reader.diag_info.unmatched_braces)
+        (res, tt_reader.diag_info.unmatched_delims)
     }
 
     // Parse a stream of tokens into a list of `TokenTree`s.
@@ -34,7 +34,7 @@ impl<'a> TokenTreesReader<'a> {
         let mut buf = Vec::new();
         loop {
             match self.token.kind {
-                token::OpenDelim(delim) => buf.push(self.parse_token_tree_open_delim(delim)),
+                token::OpenDelim(delim) => buf.push(self.parse_token_tree_open_delim(delim)?),
                 token::CloseDelim(delim) => {
                     return if is_delimited {
                         Ok(TokenStream::new(buf))
@@ -43,10 +43,11 @@ impl<'a> TokenTreesReader<'a> {
                     };
                 }
                 token::Eof => {
-                    if is_delimited {
-                        self.eof_err().emit();
-                    }
-                    return Ok(TokenStream::new(buf));
+                    return if is_delimited {
+                        Err(self.eof_err())
+                    } else {
+                        Ok(TokenStream::new(buf))
+                    };
                 }
                 _ => {
                     // Get the next normal token. This might require getting multiple adjacent
@@ -78,7 +79,7 @@ impl<'a> TokenTreesReader<'a> {
         let mut err = self.string_reader.sess.span_diagnostic.struct_span_err(self.token.span, msg);
         for &(_, sp) in &self.diag_info.open_braces {
             err.span_label(sp, "unclosed delimiter");
-            self.diag_info.unmatched_braces.push(UnmatchedBrace {
+            self.diag_info.unmatched_delims.push(UnmatchedDelim {
                 expected_delim: Delimiter::Brace,
                 found_delim: None,
                 found_span: self.token.span,
@@ -98,7 +99,7 @@ impl<'a> TokenTreesReader<'a> {
         err
     }
 
-    fn parse_token_tree_open_delim(&mut self, open_delim: Delimiter) -> TokenTree {
+    fn parse_token_tree_open_delim(&mut self, open_delim: Delimiter) -> PResult<'a, TokenTree> {
         // The span for beginning of the delimited section
         let pre_span = self.token.span;
 
@@ -107,7 +108,7 @@ impl<'a> TokenTreesReader<'a> {
         // Parse the token trees within the delimiters.
         // We stop at any delimiter so we can try to recover if the user
         // uses an incorrect delimiter.
-        let tts = self.parse_token_trees(/* is_delimited */ true).unwrap();
+        let tts = self.parse_token_trees(/* is_delimited */ true)?;
 
         // Expand to cover the entire delimited token tree
         let delim_span = DelimSpan::from_pair(pre_span, self.token.span);
@@ -160,7 +161,7 @@ impl<'a> TokenTreesReader<'a> {
                         }
                     }
                     let (tok, _) = self.diag_info.open_braces.pop().unwrap();
-                    self.diag_info.unmatched_braces.push(UnmatchedBrace {
+                    self.diag_info.unmatched_delims.push(UnmatchedDelim {
                         expected_delim: tok,
                         found_delim: Some(close_delim),
                         found_span: self.token.span,
@@ -190,7 +191,7 @@ impl<'a> TokenTreesReader<'a> {
             _ => unreachable!(),
         }
 
-        TokenTree::Delimited(delim_span, open_delim, tts)
+        Ok(TokenTree::Delimited(delim_span, open_delim, tts))
     }
 
     fn close_delim_err(&mut self, delim: Delimiter) -> PErr<'a> {

compiler/rustc_parse/src/lib.rs

@@ -30,7 +30,7 @@ pub const MACRO_ARGUMENTS: Option<&str> = Some("macro arguments");
 
 #[macro_use]
 pub mod parser;
-use parser::{emit_unclosed_delims, make_unclosed_delims_error, Parser};
+use parser::{make_unclosed_delims_error, Parser};
 pub mod lexer;
 pub mod validate_attr;
 
@@ -96,10 +96,7 @@ pub fn parse_stream_from_source_str(
     sess: &ParseSess,
     override_span: Option<Span>,
 ) -> TokenStream {
-    let (stream, mut errors) =
-        source_file_to_stream(sess, sess.source_map().new_source_file(name, source), override_span);
-    emit_unclosed_delims(&mut errors, &sess);
-    stream
+    source_file_to_stream(sess, sess.source_map().new_source_file(name, source), override_span)
 }
 
 /// Creates a new parser from a source string.
@@ -135,9 +132,8 @@ fn maybe_source_file_to_parser(
     source_file: Lrc<SourceFile>,
 ) -> Result<Parser<'_>, Vec<Diagnostic>> {
     let end_pos = source_file.end_pos;
-    let (stream, unclosed_delims) = maybe_file_to_stream(sess, source_file, None)?;
+    let stream = maybe_file_to_stream(sess, source_file, None)?;
     let mut parser = stream_to_parser(sess, stream, None);
-    parser.unclosed_delims = unclosed_delims;
     if parser.token == token::Eof {
         parser.token.span = Span::new(end_pos, end_pos, parser.token.span.ctxt(), None);
     }
@@ -182,7 +178,7 @@ pub fn source_file_to_stream(
     sess: &ParseSess,
     source_file: Lrc<SourceFile>,
     override_span: Option<Span>,
-) -> (TokenStream, Vec<lexer::UnmatchedBrace>) {
+) -> TokenStream {
     panictry_buffer!(&sess.span_diagnostic, maybe_file_to_stream(sess, source_file, override_span))
 }
 
@@ -192,31 +188,15 @@ pub fn maybe_file_to_stream(
     sess: &ParseSess,
     source_file: Lrc<SourceFile>,
     override_span: Option<Span>,
-) -> Result<(TokenStream, Vec<lexer::UnmatchedBrace>), Vec<Diagnostic>> {
+) -> Result<TokenStream, Vec<Diagnostic>> {
     let src = source_file.src.as_ref().unwrap_or_else(|| {
         sess.span_diagnostic.bug(&format!(
             "cannot lex `source_file` without source: {}",
             sess.source_map().filename_for_diagnostics(&source_file.name)
         ));
     });
 
-    let (token_trees, unmatched_braces) =
-        lexer::parse_token_trees(sess, src.as_str(), source_file.start_pos, override_span);
-
-    match token_trees {
-        Ok(stream) => Ok((stream, unmatched_braces)),
-        Err(err) => {
-            let mut buffer = Vec::with_capacity(1);
-            err.buffer(&mut buffer);
-            // Not using `emit_unclosed_delims` to use `db.buffer`
-            for unmatched in unmatched_braces {
-                if let Some(err) = make_unclosed_delims_error(unmatched, &sess) {
-                    err.buffer(&mut buffer);
-                }
-            }
-            Err(buffer)
-        }
-    }
+    lexer::parse_token_trees(sess, src.as_str(), source_file.start_pos, override_span)
 }
 
 /// Given a stream and the `ParseSess`, produces a parser.

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -19,7 +19,7 @@ use crate::errors::{
 };
 
 use crate::fluent_generated as fluent;
-use crate::lexer::UnmatchedBrace;
+use crate::lexer::UnmatchedDelim;
 use crate::parser;
 use rustc_ast as ast;
 use rustc_ast::ptr::P;
@@ -222,7 +222,7 @@ impl MultiSugg {
 /// is dropped.
 pub struct SnapshotParser<'a> {
     parser: Parser<'a>,
-    unclosed_delims: Vec<UnmatchedBrace>,
+    unclosed_delims: Vec<UnmatchedDelim>,
 }
 
 impl<'a> Deref for SnapshotParser<'a> {
@@ -264,7 +264,7 @@ impl<'a> Parser<'a> {
         self.unclosed_delims.extend(snapshot.unclosed_delims);
     }
 
-    pub fn unclosed_delims(&self) -> &[UnmatchedBrace] {
+    pub fn unclosed_delims(&self) -> &[UnmatchedDelim] {
         &self.unclosed_delims
     }
 

compiler/rustc_parse/src/parser/mod.rs

@@ -10,7 +10,7 @@ mod path;
 mod stmt;
 mod ty;
 
-use crate::lexer::UnmatchedBrace;
+use crate::lexer::UnmatchedDelim;
 pub use attr_wrapper::AttrWrapper;
 pub use diagnostics::AttemptLocalParseRecovery;
 pub(crate) use item::FnParseMode;
@@ -149,7 +149,7 @@ pub struct Parser<'a> {
     /// A list of all unclosed delimiters found by the lexer. If an entry is used for error recovery
     /// it gets removed from here. Every entry left at the end gets emitted as an independent
     /// error.
-    pub(super) unclosed_delims: Vec<UnmatchedBrace>,
+    pub(super) unclosed_delims: Vec<UnmatchedDelim>,
     last_unexpected_token_span: Option<Span>,
     /// Span pointing at the `:` for the last type ascription the parser has seen, and whether it
     /// looked like it could have been a mistyped path or literal `Option:Some(42)`).
@@ -1521,11 +1521,11 @@ impl<'a> Parser<'a> {
 }
 
 pub(crate) fn make_unclosed_delims_error(
-    unmatched: UnmatchedBrace,
+    unmatched: UnmatchedDelim,
     sess: &ParseSess,
 ) -> Option<DiagnosticBuilder<'_, ErrorGuaranteed>> {
     // `None` here means an `Eof` was found. We already emit those errors elsewhere, we add them to
-    // `unmatched_braces` only for error recovery in the `Parser`.
+    // `unmatched_delims` only for error recovery in the `Parser`.
     let found_delim = unmatched.found_delim?;
     let mut spans = vec![unmatched.found_span];
     if let Some(sp) = unmatched.unclosed_span {
@@ -1542,7 +1542,7 @@ pub(crate) fn make_unclosed_delims_error(
     Some(err)
 }
 
-pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, sess: &ParseSess) {
+pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedDelim>, sess: &ParseSess) {
     *sess.reached_eof.borrow_mut() |=
         unclosed_delims.iter().any(|unmatched_delim| unmatched_delim.found_delim.is_none());
     for unmatched in unclosed_delims.drain(..) {

src/librustdoc/doctest.rs

@@ -769,24 +769,16 @@ fn check_if_attr_is_complete(source: &str, edition: Edition) -> bool {
                 match maybe_new_parser_from_source_str(&sess, filename, source.to_owned()) {
                     Ok(p) => p,
                     Err(_) => {
-                        debug!("Cannot build a parser to check mod attr so skipping...");
-                        return true;
+                        // If there is an unclosed delimiter, an error will be returned by the tokentrees.
+                        return false;
                     }
                 };
             // If a parsing error happened, it's very likely that the attribute is incomplete.
             if let Err(e) = parser.parse_attribute(InnerAttrPolicy::Permitted) {
                 e.cancel();
                 return false;
             }
-            // We now check if there is an unclosed delimiter for the attribute. To do so, we look at
-            // the `unclosed_delims` and see if the opening square bracket was closed.
-            parser
-                .unclosed_delims()
-                .get(0)
-                .map(|unclosed| {
-                    unclosed.unclosed_span.map(|s| s.lo()).unwrap_or(BytePos(0)) != BytePos(2)
-                })
-                .unwrap_or(true)
+            true
         })
     })
     .unwrap_or(false)

tests/ui/lint/issue-104897.rs

@@ -1,6 +1,5 @@
 // error-pattern: this file contains an unclosed delimiter
 // error-pattern: this file contains an unclosed delimiter
 // error-pattern: this file contains an unclosed delimiter
-// error-pattern: format argument must be a string literal
 
 fn f(){(print!(á