Auto merge of #69129 - Centril:macro-legacy-errors, r=petrochenkov

Transition macro_legacy_warnings into a hard error

Fixes https://github.com/rust-lang/rust/issues/67098.

r? @petrochenkov

1 files changed, 9 insertions, 53 deletions

diff --git a/src/librustc_parse/parser/stmt.rs b/src/librustc_parse/parser/stmt.rs
index 742fc4802fd..0ce0e0df66a 100644
--- a/src/librustc_parse/parser/stmt.rs
+++ b/src/librustc_parse/parser/stmt.rs
@@ -22,17 +22,14 @@ impl<'a> Parser<'a> {
     /// Parses a statement. This stops just before trailing semicolons on everything but items.
     /// e.g., a `StmtKind::Semi` parses to a `StmtKind::Expr`, leaving the trailing `;` unconsumed.
     pub fn parse_stmt(&mut self) -> PResult<'a, Option<Stmt>> {
-        Ok(self.parse_stmt_without_recovery(true).unwrap_or_else(|mut e| {
+        Ok(self.parse_stmt_without_recovery().unwrap_or_else(|mut e| {
             e.emit();
             self.recover_stmt_(SemiColonMode::Break, BlockMode::Ignore);
             None
         }))
     }
 
-    fn parse_stmt_without_recovery(
-        &mut self,
-        macro_legacy_warnings: bool,
-    ) -> PResult<'a, Option<Stmt>> {
+    fn parse_stmt_without_recovery(&mut self) -> PResult<'a, Option<Stmt>> {
         maybe_whole!(self, NtStmt, |x| Some(x));
 
         let attrs = self.parse_outer_attributes()?;
@@ -64,7 +61,7 @@ impl<'a> Parser<'a> {
             let path = self.parse_path(PathStyle::Expr)?;
 
             if self.eat(&token::Not) {
-                return self.parse_stmt_mac(lo, attrs.into(), path, macro_legacy_warnings);
+                return self.parse_stmt_mac(lo, attrs.into(), path);
             }
 
             let expr = if self.check(&token::OpenDelim(token::Brace)) {
@@ -127,7 +124,6 @@ impl<'a> Parser<'a> {
         lo: Span,
         attrs: AttrVec,
         path: ast::Path,
-        legacy_warnings: bool,
     ) -> PResult<'a, Option<Stmt>> {
         let args = self.parse_mac_args()?;
         let delim = args.delim();
@@ -140,30 +136,6 @@ impl<'a> Parser<'a> {
 
         let kind = if delim == token::Brace || self.token == token::Semi || self.token == token::Eof
         {
-            StmtKind::Mac(P((mac, style, attrs.into())))
-        }
-        // We used to incorrectly stop parsing macro-expanded statements here.
-        // If the next token will be an error anyway but could have parsed with the
-        // earlier behavior, stop parsing here and emit a warning to avoid breakage.
-        else if legacy_warnings
-            && self.token.can_begin_expr()
-            && match self.token.kind {
-                // These can continue an expression, so we can't stop parsing and warn.
-                token::OpenDelim(token::Paren)
-                | token::OpenDelim(token::Bracket)
-                | token::BinOp(token::Minus)
-                | token::BinOp(token::Star)
-                | token::BinOp(token::And)
-                | token::BinOp(token::Or)
-                | token::AndAnd
-                | token::OrOr
-                | token::DotDot
-                | token::DotDotDot
-                | token::DotDotEq => false,
-                _ => true,
-            }
-        {
-            self.warn_missing_semicolon();
             StmtKind::Mac(P((mac, style, attrs)))
         } else {
             // Since none of the above applied, this is an expression statement macro.
@@ -310,7 +282,7 @@ impl<'a> Parser<'a> {
         //      bar;
         //
         // which is valid in other languages, but not Rust.
-        match self.parse_stmt_without_recovery(false) {
+        match self.parse_stmt_without_recovery() {
             Ok(Some(stmt)) => {
                 if self.look_ahead(1, |t| t == &token::OpenDelim(token::Brace))
                     || do_not_suggest_help
@@ -369,7 +341,7 @@ impl<'a> Parser<'a> {
             if self.token == token::Eof {
                 break;
             }
-            let stmt = match self.parse_full_stmt(false) {
+            let stmt = match self.parse_full_stmt() {
                 Err(mut err) => {
                     self.maybe_annotate_with_ascription(&mut err, false);
                     err.emit();
@@ -389,11 +361,11 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a statement, including the trailing semicolon.
-    pub fn parse_full_stmt(&mut self, macro_legacy_warnings: bool) -> PResult<'a, Option<Stmt>> {
+    pub fn parse_full_stmt(&mut self) -> PResult<'a, Option<Stmt>> {
         // Skip looking for a trailing semicolon when we have an interpolated statement.
         maybe_whole!(self, NtStmt, |x| Some(x));
 
-        let mut stmt = match self.parse_stmt_without_recovery(macro_legacy_warnings)? {
+        let mut stmt = match self.parse_stmt_without_recovery()? {
             Some(stmt) => stmt,
             None => return Ok(None),
         };
@@ -433,13 +405,8 @@ impl<'a> Parser<'a> {
                 }
             }
             StmtKind::Local(..) => {
-                // We used to incorrectly allow a macro-expanded let statement to lack a semicolon.
-                if macro_legacy_warnings && self.token != token::Semi {
-                    self.warn_missing_semicolon();
-                } else {
-                    self.expect_semi()?;
-                    eat_semi = false;
-                }
+                self.expect_semi()?;
+                eat_semi = false;
             }
             _ => {}
         }
@@ -451,17 +418,6 @@ impl<'a> Parser<'a> {
         Ok(Some(stmt))
     }
 
-    fn warn_missing_semicolon(&self) {
-        self.diagnostic()
-            .struct_span_warn(self.token.span, {
-                &format!("expected `;`, found {}", super::token_descr(&self.token))
-            })
-            .note({
-                "this was erroneously allowed and will become a hard error in a future release"
-            })
-            .emit();
-    }
-
     pub(super) fn mk_block(&self, stmts: Vec<Stmt>, rules: BlockCheckMode, span: Span) -> P<Block> {
         P(Block { stmts, id: DUMMY_NODE_ID, rules, span })
     }