Auto merge of #65838 - estebank:resilient-recovery, r=Centril

Reduce amount of errors given unclosed delimiter

When in a file with a non-terminated item, catch the error and consume
the block instead of trying to recover it on a more granular way in order to
reduce the amount of unrelated errors that would be fixed after adding
the missing closing brace. Also point out the possible location of the
missing closing brace.

Fix #63690.

24 files changed, 293 insertions, 153 deletions

diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index de187a3f5e0..c5f830c0d04 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -424,7 +424,7 @@ impl cstore::CStore {
         let source_file = sess.parse_sess.source_map().new_source_file(source_name, def.body);
         let local_span = Span::with_root_ctxt(source_file.start_pos, source_file.end_pos);
         let (body, mut errors) = source_file_to_stream(&sess.parse_sess, source_file, None);
-        emit_unclosed_delims(&mut errors, &sess.diagnostic());
+        emit_unclosed_delims(&mut errors, &sess.parse_sess);
 
         // Mark the attrs as used
         let attrs = data.get_item_attrs(id.index, sess);
diff --git a/src/librustc_passes/entry.rs b/src/librustc_passes/entry.rs
index bf68807a0c2..66004719060 100644
--- a/src/librustc_passes/entry.rs
+++ b/src/librustc_passes/entry.rs
@@ -154,6 +154,14 @@ fn configure_main(tcx: TyCtxt<'_>, visitor: &EntryContext<'_, '_>) -> Option<(De
 }
 
 fn no_main_err(tcx: TyCtxt<'_>, visitor: &EntryContext<'_, '_>) {
+    let sp = tcx.hir().krate().span;
+    if *tcx.sess.parse_sess.reached_eof.borrow() {
+        // There's an unclosed brace that made the parser reach `Eof`, we shouldn't complain about
+        // the missing `fn main()` then as it might have been hidden inside an unclosed block.
+        tcx.sess.delay_span_bug(sp, "`main` not found, but expected unclosed brace error");
+        return;
+    }
+
     // There is no main function.
     let mut err = struct_err!(tcx.sess, E0601,
         "`main` function not found in crate `{}`", tcx.crate_name(LOCAL_CRATE));
@@ -173,7 +181,6 @@ fn no_main_err(tcx: TyCtxt<'_>, visitor: &EntryContext<'_, '_>) {
     } else {
         String::from("consider adding a `main` function at the crate level")
     };
-    let sp = tcx.hir().krate().span;
     // The file may be empty, which leads to the diagnostic machinery not emitting this
     // note. This is a relatively simple way to detect that case and emit a span-less
     // note instead.
diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index e6dc9a4c134..48cf117f65a 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -23,7 +23,7 @@ mod unicode_chars;
 #[derive(Clone, Debug)]
 pub struct UnmatchedBrace {
     pub expected_delim: token::DelimToken,
-    pub found_delim: token::DelimToken,
+    pub found_delim: Option<token::DelimToken>,
     pub found_span: Span,
     pub unclosed_span: Option<Span>,
     pub candidate_span: Option<Span>,
diff --git a/src/libsyntax/parse/lexer/tokentrees.rs b/src/libsyntax/parse/lexer/tokentrees.rs
index 853723de14f..de8ac2c71e8 100644
--- a/src/libsyntax/parse/lexer/tokentrees.rs
+++ b/src/libsyntax/parse/lexer/tokentrees.rs
@@ -80,6 +80,13 @@ impl<'a> TokenTreesReader<'a> {
                     .struct_span_err(self.token.span, msg);
                 for &(_, sp) in &self.open_braces {
                     err.span_label(sp, "un-closed delimiter");
+                    self.unmatched_braces.push(UnmatchedBrace {
+                        expected_delim: token::DelimToken::Brace,
+                        found_delim: None,
+                        found_span: self.token.span,
+                        unclosed_span: Some(sp),
+                        candidate_span: None,
+                    });
                 }
 
                 if let Some((delim, _)) = self.open_braces.last() {
@@ -170,7 +177,7 @@ impl<'a> TokenTreesReader<'a> {
                             let (tok, _) = self.open_braces.pop().unwrap();
                             self.unmatched_braces.push(UnmatchedBrace {
                                 expected_delim: tok,
-                                found_delim: other,
+                                found_delim: Some(other),
                                 found_span: self.token.span,
                                 unclosed_span: unclosed_delimiter,
                                 candidate_span: candidate,
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index f5e416b722b..6d8ecdf805b 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -1,7 +1,7 @@
 //! The main parser interface.
 
 use crate::ast;
-use crate::parse::parser::{Parser, emit_unclosed_delims};
+use crate::parse::parser::{Parser, emit_unclosed_delims, make_unclosed_delims_error};
 use crate::parse::token::Nonterminal;
 use crate::tokenstream::{self, TokenStream, TokenTree};
 use crate::print::pprust;
@@ -108,7 +108,7 @@ pub fn parse_stream_from_source_str(
         sess.source_map().new_source_file(name, source),
         override_span,
     );
-    emit_unclosed_delims(&mut errors, &sess.span_diagnostic);
+    emit_unclosed_delims(&mut errors, &sess);
     stream
 }
 
@@ -242,18 +242,9 @@ pub fn maybe_file_to_stream(
             err.buffer(&mut buffer);
             // Not using `emit_unclosed_delims` to use `db.buffer`
             for unmatched in unmatched_braces {
-                let mut db = sess.span_diagnostic.struct_span_err(unmatched.found_span, &format!(
-                    "incorrect close delimiter: `{}`",
-                    pprust::token_kind_to_string(&token::CloseDelim(unmatched.found_delim)),
-                ));
-                db.span_label(unmatched.found_span, "incorrect close delimiter");
-                if let Some(sp) = unmatched.candidate_span {
-                    db.span_label(sp, "close delimiter possibly meant for this");
+                if let Some(err) = make_unclosed_delims_error(unmatched, &sess) {
+                    err.buffer(&mut buffer);
                 }
-                if let Some(sp) = unmatched.unclosed_span {
-                    db.span_label(sp, "un-closed delimiter");
-                }
-                db.buffer(&mut buffer);
             }
             Err(buffer)
         }
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 6ead1ce811d..e81d4573b73 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -27,7 +27,7 @@ use crate::symbol::{kw, sym, Symbol};
 use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
 use crate::ThinVec;
 
-use errors::{Applicability, DiagnosticId, FatalError};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
 use rustc_target::spec::abi::{self, Abi};
 use syntax_pos::{Span, BytePos, DUMMY_SP, FileName};
 use log::debug;
@@ -148,8 +148,7 @@ pub struct Parser<'a> {
 
 impl<'a> Drop for Parser<'a> {
     fn drop(&mut self) {
-        let diag = self.diagnostic();
-        emit_unclosed_delims(&mut self.unclosed_delims, diag);
+        emit_unclosed_delims(&mut self.unclosed_delims, &self.sess);
     }
 }
 
@@ -1370,20 +1369,31 @@ impl<'a> Parser<'a> {
     }
 }
 
-pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, handler: &errors::Handler) {
-    for unmatched in unclosed_delims.iter() {
-        let mut err = handler.struct_span_err(unmatched.found_span, &format!(
-            "incorrect close delimiter: `{}`",
-            pprust::token_kind_to_string(&token::CloseDelim(unmatched.found_delim)),
-        ));
-        err.span_label(unmatched.found_span, "incorrect close delimiter");
-        if let Some(sp) = unmatched.candidate_span {
-            err.span_label(sp, "close delimiter possibly meant for this");
-        }
-        if let Some(sp) = unmatched.unclosed_span {
-            err.span_label(sp, "un-closed delimiter");
-        }
-        err.emit();
+crate fn make_unclosed_delims_error(
+    unmatched: UnmatchedBrace,
+    sess: &ParseSess,
+) -> Option<DiagnosticBuilder<'_>> {
+    // `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`.
+    let found_delim = unmatched.found_delim?;
+    let mut err = sess.span_diagnostic.struct_span_err(unmatched.found_span, &format!(
+        "incorrect close delimiter: `{}`",
+        pprust::token_kind_to_string(&token::CloseDelim(found_delim)),
+    ));
+    err.span_label(unmatched.found_span, "incorrect close delimiter");
+    if let Some(sp) = unmatched.candidate_span {
+        err.span_label(sp, "close delimiter possibly meant for this");
+    }
+    if let Some(sp) = unmatched.unclosed_span {
+        err.span_label(sp, "un-closed delimiter");
+    }
+    Some(err)
+}
+
+pub fn emit_unclosed_delims(unclosed_delims: &mut Vec<UnmatchedBrace>, 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(..) {
+        make_unclosed_delims_error(unmatched, sess).map(|mut e| e.emit());
     }
-    unclosed_delims.clear();
 }
diff --git a/src/libsyntax/parse/parser/diagnostics.rs b/src/libsyntax/parse/parser/diagnostics.rs
index ab2b4519cb7..fcf3b4c0aa8 100644
--- a/src/libsyntax/parse/parser/diagnostics.rs
+++ b/src/libsyntax/parse/parser/diagnostics.rs
@@ -171,6 +171,12 @@ impl RecoverQPath for Expr {
     }
 }
 
+/// Control whether the closing delimiter should be consumed when calling `Parser::consume_block`.
+crate enum ConsumeClosingDelim {
+    Yes,
+    No,
+}
+
 impl<'a> Parser<'a> {
     pub fn fatal(&self, m: &str) -> DiagnosticBuilder<'a> {
         self.span_fatal(self.token.span, m)
@@ -1105,8 +1111,8 @@ impl<'a> Parser<'a> {
             Ok(x) => x,
             Err(mut err) => {
                 err.emit();
-                // Recover from parse error.
-                self.consume_block(delim);
+                // Recover from parse error, callers expect the closing delim to be consumed.
+                self.consume_block(delim, ConsumeClosingDelim::Yes);
                 self.mk_expr(lo.to(self.prev_span), ExprKind::Err, ThinVec::new())
             }
         }
@@ -1135,6 +1141,11 @@ impl<'a> Parser<'a> {
                  // Don't attempt to recover from this unclosed delimiter more than once.
                 let unmatched = self.unclosed_delims.remove(pos);
                 let delim = TokenType::Token(token::CloseDelim(unmatched.expected_delim));
+                if unmatched.found_delim.is_none() {
+                    // We encountered `Eof`, set this fact here to avoid complaining about missing
+                    // `fn main()` when we found place to suggest the closing brace.
+                    *self.sess.reached_eof.borrow_mut() = true;
+                }
 
                 // We want to suggest the inclusion of the closing delimiter where it makes
                 // the most sense, which is immediately after the last token:
@@ -1154,9 +1165,16 @@ impl<'a> Parser<'a> {
                     delim.to_string(),
                     Applicability::MaybeIncorrect,
                 );
-                err.emit();
-                self.expected_tokens.clear();  // reduce errors
-                Ok(true)
+                if unmatched.found_delim.is_none() {
+                    // Encountered `Eof` when lexing blocks. Do not recover here to avoid knockdown
+                    // errors which would be emitted elsewhere in the parser and let other error
+                    // recovery consume the rest of the file.
+                    Err(err)
+                } else {
+                    err.emit();
+                    self.expected_tokens.clear();  // Reduce the number of errors.
+                    Ok(true)
+                }
             }
             _ => Err(err),
         }
@@ -1164,7 +1182,12 @@ impl<'a> Parser<'a> {
 
     /// Recovers from `pub` keyword in places where it seems _reasonable_ but isn't valid.
     pub(super) fn eat_bad_pub(&mut self) {
-        if self.token.is_keyword(kw::Pub) {
+        // When `unclosed_delims` is populated, it means that the code being parsed is already
+        // quite malformed, which might mean that, for example, a pub struct definition could be
+        // parsed as being a trait item, which is invalid and this error would trigger
+        // unconditionally, resulting in misleading diagnostics. Because of this, we only attempt
+        // this nice to have recovery for code that is otherwise well formed.
+        if self.token.is_keyword(kw::Pub) && self.unclosed_delims.is_empty() {
             match self.parse_visibility(false) {
                 Ok(vis) => {
                     self.diagnostic()
@@ -1422,15 +1445,26 @@ impl<'a> Parser<'a> {
         Ok(param)
     }
 
-    pub(super) fn consume_block(&mut self, delim: token::DelimToken) {
+    pub(super) fn consume_block(
+        &mut self,
+        delim: token::DelimToken,
+        consume_close: ConsumeClosingDelim,
+    ) {
         let mut brace_depth = 0;
         loop {
             if self.eat(&token::OpenDelim(delim)) {
                 brace_depth += 1;
-            } else if self.eat(&token::CloseDelim(delim)) {
+            } else if self.check(&token::CloseDelim(delim)) {
                 if brace_depth == 0 {
+                    if let ConsumeClosingDelim::Yes = consume_close {
+                        // Some of the callers of this method expect to be able to parse the
+                        // closing delimiter themselves, so we leave it alone. Otherwise we advance
+                        // the parser.
+                        self.bump();
+                    }
                     return;
                 } else {
+                    self.bump();
                     brace_depth -= 1;
                     continue;
                 }
diff --git a/src/libsyntax/parse/parser/item.rs b/src/libsyntax/parse/parser/item.rs
index fe125336190..5b60e7e6dba 100644
--- a/src/libsyntax/parse/parser/item.rs
+++ b/src/libsyntax/parse/parser/item.rs
@@ -1,5 +1,5 @@
-use super::{Parser, PResult, PathStyle, SemiColonMode, BlockMode};
-use super::diagnostics::{Error, dummy_arg};
+use super::{Parser, PResult, PathStyle};
+use super::diagnostics::{Error, dummy_arg, ConsumeClosingDelim};
 
 use crate::maybe_whole;
 use crate::ptr::P;
@@ -339,7 +339,7 @@ impl<'a> Parser<'a> {
                 let ident = self.parse_ident().unwrap();
                 self.bump();  // `(`
                 let kw_name = self.recover_first_param();
-                self.consume_block(token::Paren);
+                self.consume_block(token::Paren, ConsumeClosingDelim::Yes);
                 let (kw, kw_name, ambiguous) = if self.check(&token::RArrow) {
                     self.eat_to_tokens(&[&token::OpenDelim(token::Brace)]);
                     self.bump();  // `{`
@@ -357,7 +357,7 @@ impl<'a> Parser<'a> {
                 let msg = format!("missing `{}` for {} definition", kw, kw_name);
                 let mut err = self.diagnostic().struct_span_err(sp, &msg);
                 if !ambiguous {
-                    self.consume_block(token::Brace);
+                    self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
                     let suggestion = format!("add `{}` here to parse `{}` as a public {}",
                                              kw,
                                              ident,
@@ -672,7 +672,8 @@ impl<'a> Parser<'a> {
                 Err(mut err) => {
                     err.emit();
                     if !at_end {
-                        self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
+                        self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
+                        break;
                     }
                 }
             }
@@ -861,7 +862,8 @@ impl<'a> Parser<'a> {
                     Err(mut e) => {
                         e.emit();
                         if !at_end {
-                            self.recover_stmt_(SemiColonMode::Break, BlockMode::Break);
+                            self.consume_block(token::Brace, ConsumeClosingDelim::Yes);
+                            break;
                         }
                     }
                 }
@@ -1520,7 +1522,7 @@ impl<'a> Parser<'a> {
         if self.eat(&token::OpenDelim(token::Brace)) {
             while self.token != token::CloseDelim(token::Brace) {
                 let field = self.parse_struct_decl_field().map_err(|e| {
-                    self.recover_stmt();
+                    self.consume_block(token::Brace, ConsumeClosingDelim::No);
                     recovered = true;
                     e
                 });
@@ -1528,6 +1530,7 @@ impl<'a> Parser<'a> {
                     Ok(field) => fields.push(field),
                     Err(mut err) => {
                         err.emit();
+                        break;
                     }
                 }
             }
diff --git a/src/libsyntax/sess.rs b/src/libsyntax/sess.rs
index 28a0868d5dd..323fe01f067 100644
--- a/src/libsyntax/sess.rs
+++ b/src/libsyntax/sess.rs
@@ -73,6 +73,8 @@ pub struct ParseSess {
     pub ambiguous_block_expr_parse: Lock<FxHashMap<Span, Span>>,
     pub injected_crate_name: Once<Symbol>,
     crate gated_spans: GatedSpans,
+    /// The parser has reached `Eof` due to an unclosed brace. Used to silence unnecessary errors.
+    pub reached_eof: Lock<bool>,
 }
 
 impl ParseSess {
@@ -101,6 +103,7 @@ impl ParseSess {
             ambiguous_block_expr_parse: Lock::new(FxHashMap::default()),
             injected_crate_name: Once::new(),
             gated_spans: GatedSpans::default(),
+            reached_eof: Lock::new(false),
         }
     }
 
diff --git a/src/test/ui/did_you_mean/issue-40006.rs b/src/test/ui/did_you_mean/issue-40006.rs
index a1184f757e2..b3c1f60b7eb 100644
--- a/src/test/ui/did_you_mean/issue-40006.rs
+++ b/src/test/ui/did_you_mean/issue-40006.rs
@@ -1,5 +1,4 @@
-impl dyn X { //~ ERROR cannot be made into an object
-//~^ ERROR missing
+impl dyn A { //~ ERROR missing
     Y
 }
 
@@ -7,10 +6,25 @@ struct S;
 
 trait X { //~ ERROR missing
     X() {}
-    fn xxx() { ### } //~ ERROR missing
-    //~^ ERROR expected
-    L = M; //~ ERROR missing
-    Z = { 2 + 3 }; //~ ERROR expected one of
+    fn xxx() { ### }
+    L = M;
+    Z = { 2 + 3 };
+    ::Y ();
+}
+
+trait A { //~ ERROR missing
+    X() {}
+}
+trait B {
+    fn xxx() { ### } //~ ERROR expected
+}
+trait C { //~ ERROR missing `fn`, `type`, or `const` for trait-item declaration
+    L = M;
+}
+trait D { //~ ERROR missing `fn`, `type`, or `const` for trait-item declaration
+    Z = { 2 + 3 };
+}
+trait E {
     ::Y (); //~ ERROR expected one of
 }
 
@@ -21,5 +35,5 @@ impl S {
 }
 
 fn main() {
-    S.hello_method();
+    S.hello_method(); //~ no method named `hello_method` found for type `S` in the current scope
 }
diff --git a/src/test/ui/did_you_mean/issue-40006.stderr b/src/test/ui/did_you_mean/issue-40006.stderr
index 5b384045a48..f0baa175d63 100644
--- a/src/test/ui/did_you_mean/issue-40006.stderr
+++ b/src/test/ui/did_you_mean/issue-40006.stderr
@@ -1,70 +1,70 @@
 error: missing `fn`, `type`, or `const` for impl-item declaration
   --> $DIR/issue-40006.rs:1:13
    |
-LL |   impl dyn X {
+LL |   impl dyn A {
    |  _____________^
-LL | |
 LL | |     Y
    | |____^ missing `fn`, `type`, or `const`
 
 error: missing `fn`, `type`, or `const` for trait-item declaration
-  --> $DIR/issue-40006.rs:8:10
+  --> $DIR/issue-40006.rs:7:10
    |
 LL |   trait X {
    |  __________^
 LL | |     X() {}
    | |____^ missing `fn`, `type`, or `const`
 
+error: missing `fn`, `type`, or `const` for trait-item declaration
+  --> $DIR/issue-40006.rs:15:10
+   |
+LL |   trait A {
+   |  __________^
+LL | |     X() {}
+   | |____^ missing `fn`, `type`, or `const`
+
 error: expected `[`, found `#`
-  --> $DIR/issue-40006.rs:10:17
+  --> $DIR/issue-40006.rs:19:17
    |
 LL |     fn xxx() { ### }
    |                 ^ expected `[`
 
 error: missing `fn`, `type`, or `const` for trait-item declaration
-  --> $DIR/issue-40006.rs:10:21
+  --> $DIR/issue-40006.rs:21:10
    |
-LL |       fn xxx() { ### }
-   |  _____________________^
-LL | |
+LL |   trait C {
+   |  __________^
 LL | |     L = M;
    | |____^ missing `fn`, `type`, or `const`
 
 error: missing `fn`, `type`, or `const` for trait-item declaration
-  --> $DIR/issue-40006.rs:12:11
+  --> $DIR/issue-40006.rs:24:10
    |
-LL |       L = M;
-   |  ___________^
+LL |   trait D {
+   |  __________^
 LL | |     Z = { 2 + 3 };
    | |____^ missing `fn`, `type`, or `const`
 
-error: expected one of `async`, `const`, `extern`, `fn`, `type`, `unsafe`, or `}`, found `;`
-  --> $DIR/issue-40006.rs:13:18
-   |
-LL |     Z = { 2 + 3 };
-   |                  ^ expected one of 7 possible tokens here
-
 error: expected one of `!` or `::`, found `(`
-  --> $DIR/issue-40006.rs:14:9
+  --> $DIR/issue-40006.rs:28:9
    |
 LL |     ::Y ();
    |         ^ expected one of `!` or `::` here
 
 error: missing `fn`, `type`, or `const` for impl-item declaration
-  --> $DIR/issue-40006.rs:18:8
+  --> $DIR/issue-40006.rs:32:8
    |
 LL |     pub hello_method(&self) {
    |        ^ missing `fn`, `type`, or `const`
 
-error[E0038]: the trait `X` cannot be made into an object
-  --> $DIR/issue-40006.rs:1:6
+error[E0599]: no method named `hello_method` found for type `S` in the current scope
+  --> $DIR/issue-40006.rs:38:7
    |
-LL | impl dyn X {
-   |      ^^^^^ the trait `X` cannot be made into an object
+LL | struct S;
+   | --------- method `hello_method` not found for this
 ...
-LL |     fn xxx() { ### }
-   |        --- associated function `xxx` has no `self` parameter
+LL |     S.hello_method();
+   |       ^^^^^^^^^^^^ method not found in `S`
 
 error: aborting due to 9 previous errors
 
-For more information about this error, try `rustc --explain E0038`.
+For more information about this error, try `rustc --explain E0599`.
diff --git a/src/test/ui/issues/issue-60075.rs b/src/test/ui/issues/issue-60075.rs
index 5788716a526..1f53a927932 100644
--- a/src/test/ui/issues/issue-60075.rs
+++ b/src/test/ui/issues/issue-60075.rs
@@ -5,8 +5,7 @@ trait T {
         let _ = if true {
         });
 //~^ ERROR expected one of `async`, `const`, `extern`, `fn`, `type`, `unsafe`, or `}`, found `;`
-//~^^ ERROR expected one of `.`, `;`, `?`, `else`, or an operator, found `}`
-//~^^^ ERROR 6:11: 6:12: expected identifier, found `;`
-//~^^^^ ERROR missing `fn`, `type`, or `const` for trait-item declaration
+//~| ERROR expected one of `.`, `;`, `?`, `else`, or an operator, found `}`
+//~| ERROR expected identifier, found `;`
         Some(4)
     }
diff --git a/src/test/ui/issues/issue-60075.stderr b/src/test/ui/issues/issue-60075.stderr
index ac97d32a6e1..961a546d8d6 100644
--- a/src/test/ui/issues/issue-60075.stderr
+++ b/src/test/ui/issues/issue-60075.stderr
@@ -19,17 +19,5 @@ error: expected identifier, found `;`
 LL |         });
    |           ^ expected identifier
 
-error: missing `fn`, `type`, or `const` for trait-item declaration
-  --> $DIR/issue-60075.rs:6:12
-   |
-LL |           });
-   |  ____________^
-LL | |
-LL | |
-LL | |
-LL | |
-LL | |         Some(4)
-   | |________^ missing `fn`, `type`, or `const`
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/parser-recovery-1.rs b/src/test/ui/parser-recovery-1.rs
index 8126525c34f..21d36048e67 100644
--- a/src/test/ui/parser-recovery-1.rs
+++ b/src/test/ui/parser-recovery-1.rs
@@ -3,7 +3,6 @@
 // Test that we can recover from missing braces in the parser.
 
 trait Foo {
-//~^ ERROR `main` function not found
     fn bar() {
         let x = foo();
         //~^ ERROR cannot find function `foo` in this scope
diff --git a/src/test/ui/parser-recovery-1.stderr b/src/test/ui/parser-recovery-1.stderr
index ffe2b3322fc..83f8ef63c99 100644
--- a/src/test/ui/parser-recovery-1.stderr
+++ b/src/test/ui/parser-recovery-1.stderr
@@ -1,9 +1,8 @@
 error: this file contains an un-closed delimiter
-  --> $DIR/parser-recovery-1.rs:16:55
+  --> $DIR/parser-recovery-1.rs:15:55
    |
 LL | trait Foo {
    |           - un-closed delimiter
-LL |
 LL |     fn bar() {
    |              - this delimiter might not be properly closed...
 ...
@@ -14,36 +13,23 @@ LL | }
    |                                                       ^
 
 error: unexpected token: `;`
-  --> $DIR/parser-recovery-1.rs:13:15
+  --> $DIR/parser-recovery-1.rs:12:15
    |
 LL |     let x = y.;
    |               ^
 
 error[E0425]: cannot find function `foo` in this scope
-  --> $DIR/parser-recovery-1.rs:8:17
+  --> $DIR/parser-recovery-1.rs:7:17
    |
 LL |         let x = foo();
    |                 ^^^ not found in this scope
 
 error[E0425]: cannot find value `y` in this scope
-  --> $DIR/parser-recovery-1.rs:13:13
+  --> $DIR/parser-recovery-1.rs:12:13
    |
 LL |     let x = y.;
    |             ^ not found in this scope
 
-error[E0601]: `main` function not found in crate `parser_recovery_1`
-  --> $DIR/parser-recovery-1.rs:5:1
-   |
-LL | / trait Foo {
-LL | |
-LL | |     fn bar() {
-LL | |         let x = foo();
-...  |
-LL | |
-LL | | }
-   | |______________________________________________________^ consider adding a `main` function to `$DIR/parser-recovery-1.rs`
-
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0425, E0601.
-For more information about an error, try `rustc --explain E0425`.
+For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/parser/issue-2354.rs b/src/test/ui/parser/issue-2354.rs
index a14eb6e32fc..c4fc4716182 100644
--- a/src/test/ui/parser/issue-2354.rs
+++ b/src/test/ui/parser/issue-2354.rs
@@ -1,7 +1,4 @@
 fn foo() { //~ NOTE un-closed delimiter
-//~^ ERROR `main` function not found
-//~^^ NOTE main function must be defined
-//~^^^ NOTE you have one or more functions
   match Some(10) {
   //~^ NOTE this delimiter might not be properly closed...
       Some(y) => { panic!(); }
@@ -14,5 +11,5 @@ fn bar() {
     while (i < 1000) {}
 }
 
-fn main() {} //~ NOTE here is a function named `main`
-             //~ ERROR this file contains an un-closed delimiter
+fn main() {}
+//~ ERROR this file contains an un-closed delimiter
diff --git a/src/test/ui/parser/issue-2354.stderr b/src/test/ui/parser/issue-2354.stderr
index 038e3dcfa40..45199b02cb8 100644
--- a/src/test/ui/parser/issue-2354.stderr
+++ b/src/test/ui/parser/issue-2354.stderr
@@ -1,9 +1,8 @@
 error: this file contains an un-closed delimiter
-  --> $DIR/issue-2354.rs:18:66
+  --> $DIR/issue-2354.rs:15:53
    |
 LL | fn foo() {
    |          - un-closed delimiter
-...
 LL |   match Some(10) {
    |                  - this delimiter might not be properly closed...
 ...
@@ -11,28 +10,7 @@ LL | }
    | - ...as it matches this but it has different indentation
 ...
 LL |
-   |                                                                  ^
-
-error[E0601]: `main` function not found in crate `issue_2354`
-  --> $DIR/issue-2354.rs:1:1
-   |
-LL | / fn foo() {
-LL | |
-LL | |
-LL | |
-...  |
-LL | | fn main() {}
-LL | |
-   | |_________________________________________________________________^ the main function must be defined at the crate level (in `$DIR/issue-2354.rs`)
-   |
-note: here is a function named `main`
-  --> $DIR/issue-2354.rs:17:1
-   |
-LL | fn main() {}
-   | ^^^^^^^^^^^^
-   = note: you have one or more functions named `main` not defined at the crate level
-   = help: either move the `main` function definitions or attach the `#[main]` attribute to one of them
+   |                                                     ^
 
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0601`.
diff --git a/src/test/ui/parser/issue-62973.stderr b/src/test/ui/parser/issue-62973.stderr
index e73776dc7b4..82122ef0b6f 100644
--- a/src/test/ui/parser/issue-62973.stderr
+++ b/src/test/ui/parser/issue-62973.stderr
@@ -13,9 +13,11 @@ error: expected one of `,` or `}`, found `{`
   --> $DIR/issue-62973.rs:6:25
    |
 LL | fn p() { match s { v, E { [) {) }
-   |                -        ^ expected one of `,` or `}` here
-   |                |
-   |                while parsing this struct
+   |        -       -       -^ expected one of `,` or `}` here
+   |        |       |       |
+   |        |       |       help: `}` may belong here
+   |        |       while parsing this struct
+   |        unclosed delimiter
 
 error: struct literals are not allowed here
   --> $DIR/issue-62973.rs:6:16
diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.rs b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.rs
new file mode 100644
index 00000000000..8d89905909e
--- /dev/null
+++ b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.rs
@@ -0,0 +1,12 @@
+impl T for () { //~ ERROR cannot find trait `T` in this scope
+
+fn foo(&self) {}
+
+trait T { //~ ERROR expected one of
+    fn foo(&self);
+}
+
+pub(crate) struct Bar<T>();
+
+fn main() {}
+//~ ERROR this file contains an un-closed delimiter
diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.stderr b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.stderr
new file mode 100644
index 00000000000..9bf54181a07
--- /dev/null
+++ b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-impl-trait.stderr
@@ -0,0 +1,33 @@
+error: this file contains an un-closed delimiter
+  --> $DIR/missing-close-brace-in-impl-trait.rs:12:53
+   |
+LL | impl T for () {
+   |               - un-closed delimiter
+...
+LL |
+   |                                                     ^
+
+error: expected one of `async`, `const`, `crate`, `default`, `extern`, `fn`, `pub`, `type`, `unsafe`, or `}`, found keyword `trait`
+  --> $DIR/missing-close-brace-in-impl-trait.rs:5:1
+   |
+LL | impl T for () {
+   |               - unclosed delimiter
+LL | 
+LL | fn foo(&self) {}
+   |                 -
+   |                 |
+   |                 expected one of 10 possible tokens here
+   |                 help: `}` may belong here
+LL | 
+LL | trait T {
+   | ^^^^^ unexpected token
+
+error[E0405]: cannot find trait `T` in this scope
+  --> $DIR/missing-close-brace-in-impl-trait.rs:1:6
+   |
+LL | impl T for () {
+   |      ^ not found in this scope
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0405`.
diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-struct.rs b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-struct.rs
new file mode 100644
index 00000000000..5b716b1467c
--- /dev/null
+++ b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-struct.rs
@@ -0,0 +1,14 @@
+pub(crate) struct Bar<T> {
+  foo: T,
+
+trait T { //~ ERROR expected identifier, found keyword `trait`
+//~^ ERROR expected `:`, found `T`
+    fn foo(&self);
+}
+
+
+impl T for Bar<usize> {
+fn foo(&self) {}
+}
+
+fn main() {} //~ ERROR this file contains an un-closed delimiter
diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-struct.stderr b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-struct.stderr
new file mode 100644
index 00000000000..ce399dbbf45
--- /dev/null
+++ b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-struct.stderr
@@ -0,0 +1,28 @@
+error: this file contains an un-closed delimiter
+  --> $DIR/missing-close-brace-in-struct.rs:14:66
+   |
+LL | pub(crate) struct Bar<T> {
+   |                          - un-closed delimiter
+...
+LL | fn main() {}
+   |                                                                  ^
+
+error: expected identifier, found keyword `trait`
+  --> $DIR/missing-close-brace-in-struct.rs:4:1
+   |
+LL | trait T {
+   | ^^^^^ expected identifier, found keyword
+   |
+help: you can escape reserved keywords to use them as identifiers
+   |
+LL | r#trait T {
+   | ^^^^^^^
+
+error: expected `:`, found `T`
+  --> $DIR/missing-close-brace-in-struct.rs:4:7
+   |
+LL | trait T {
+   |       ^ expected `:`
+
+error: aborting due to 3 previous errors
+
diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.rs b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.rs
new file mode 100644
index 00000000000..79547195411
--- /dev/null
+++ b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.rs
@@ -0,0 +1,10 @@
+trait T {
+    fn foo(&self);
+
+pub(crate) struct Bar<T>(); //~ ERROR expected one of
+
+impl T for Bar<usize> {
+fn foo(&self) {}
+}
+
+fn main() {} //~ ERROR this file contains an un-closed delimiter
diff --git a/src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.stderr b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.stderr
new file mode 100644
index 00000000000..4bfb4c1cb3a
--- /dev/null
+++ b/src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.stderr
@@ -0,0 +1,25 @@
+error: this file contains an un-closed delimiter
+  --> $DIR/missing-close-brace-in-trait.rs:10:66
+   |
+LL | trait T {
+   |         - un-closed delimiter
+...
+LL | fn main() {}
+   |                                                                  ^
+
+error: expected one of `async`, `const`, `extern`, `fn`, `type`, `unsafe`, or `}`, found keyword `pub`
+  --> $DIR/missing-close-brace-in-trait.rs:4:1
+   |
+LL | trait T {
+   |         - unclosed delimiter
+LL |     fn foo(&self);
+   |                   -
+   |                   |
+   |                   expected one of 7 possible tokens here
+   |                   help: `}` may belong here
+LL | 
+LL | pub(crate) struct Bar<T>();
+   | ^^^ unexpected token
+
+error: aborting due to 2 previous errors
+