Do not complain about missing main when a block has been recovered

src/librustc_parse/parser/diagnostics.rs

@@ -1397,6 +1397,12 @@ impl<'a> Parser<'a> {
         consume_close: ConsumeClosingDelim,
     ) {
         let mut brace_depth = 0;
+        // Avoid complaining about main in
+        // `src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.rs`.
+        // We set this here because we can't be sure that we're not going to hit `Eof` shortly
+        // afterwards, but handling this case in other parts of the parser would complicate the
+        // logic too much.
+        *self.sess.reached_eof.borrow_mut() = true;
         loop {
             if self.eat(&token::OpenDelim(delim)) {
                 brace_depth += 1;

src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.rs

@@ -1,5 +1,4 @@
 trait T {
-//~^ ERROR `main` function not found in crate `missing_close_brace_in_trait`
     fn foo(&self);
 
 pub(crate) struct Bar<T>();

src/test/ui/parser/mismatched-braces/missing-close-brace-in-trait.stderr

@@ -1,5 +1,5 @@
 error: this file contains an unclosed delimiter
-  --> $DIR/missing-close-brace-in-trait.rs:12:65
+  --> $DIR/missing-close-brace-in-trait.rs:11:65
    |
 LL | trait T {
    |         - unclosed delimiter
@@ -8,23 +8,10 @@ LL | fn main() {}
    |                                                                 ^
 
 error: expected one of `async`, `const`, `default`, `extern`, `fn`, `type`, or `unsafe`, found keyword `struct`
-  --> $DIR/missing-close-brace-in-trait.rs:5:12
+  --> $DIR/missing-close-brace-in-trait.rs:4:12
    |
 LL | pub(crate) struct Bar<T>();
    |            ^^^^^^ expected one of 7 possible tokens
 
-error[E0601]: `main` function not found in crate `missing_close_brace_in_trait`
-  --> $DIR/missing-close-brace-in-trait.rs:1:1
-   |
-LL | / trait T {
-LL | |
-LL | |     fn foo(&self);
-LL | |
-...  |
-LL | |
-LL | | fn main() {}
-   | |________________________________________________________________^ consider adding a `main` function to `$DIR/missing-close-brace-in-trait.rs`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0601`.