Avoid producing NoDelim values in MacArgs::delim().

compiler/rustc_ast/src/ast.rs

@@ -1542,10 +1542,10 @@ pub enum MacArgs {
 }
 
 impl MacArgs {
-    pub fn delim(&self) -> DelimToken {
+    pub fn delim(&self) -> Option<DelimToken> {
         match self {
-            MacArgs::Delimited(_, delim, _) => delim.to_token(),
+            MacArgs::Delimited(_, delim, _) => Some(delim.to_token()),
-            MacArgs::Empty | MacArgs::Eq(..) => token::NoDelim,
+            MacArgs::Empty | MacArgs::Eq(..) => None,
         }
     }
 

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -464,7 +464,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                 Some(MacHeader::Path(&item.path)),
                 false,
                 None,
-                delim.to_token(),
+                Some(delim.to_token()),
                 tokens,
                 true,
                 span,
@@ -530,7 +530,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                     None,
                     false,
                     None,
-                    *delim,
+                    Some(*delim),
                     tts,
                     convert_dollar_crate,
                     dspan.entire(),
@@ -556,12 +556,12 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
         header: Option<MacHeader<'_>>,
         has_bang: bool,
         ident: Option<Ident>,
-        delim: DelimToken,
+        delim: Option<DelimToken>,
         tts: &TokenStream,
         convert_dollar_crate: bool,
         span: Span,
     ) {
-        if delim == DelimToken::Brace {
+        if delim == Some(DelimToken::Brace) {
             self.cbox(INDENT_UNIT);
         }
         match header {
@@ -577,7 +577,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
             self.print_ident(ident);
         }
         match delim {
-            DelimToken::Brace => {
+            Some(DelimToken::Brace) => {
                 if header.is_some() || has_bang || ident.is_some() {
                     self.nbsp();
                 }
@@ -585,23 +585,25 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
                 if !tts.is_empty() {
                     self.space();
                 }
-            }
-            _ => {
-                let token_str = self.token_kind_to_string(&token::OpenDelim(delim));
-                self.word(token_str)
-            }
-        }
                 self.ibox(0);
                 self.print_tts(tts, convert_dollar_crate);
                 self.end();
-        match delim {
-            DelimToken::Brace => {
                 let empty = tts.is_empty();
                 self.bclose(span, empty);
             }
-            _ => {
+            Some(delim) => {
+                let token_str = self.token_kind_to_string(&token::OpenDelim(delim));
+                self.word(token_str);
+                self.ibox(0);
+                self.print_tts(tts, convert_dollar_crate);
+                self.end();
                 let token_str = self.token_kind_to_string(&token::CloseDelim(delim));
-                self.word(token_str)
+                self.word(token_str);
+            }
+            None => {
+                self.ibox(0);
+                self.print_tts(tts, convert_dollar_crate);
+                self.end();
             }
         }
     }

compiler/rustc_parse/src/parser/stmt.rs

@@ -164,13 +164,17 @@ impl<'a> Parser<'a> {
         let delim = args.delim();
         let hi = self.prev_token.span;
 
-        let style =
+        let style = match delim {
-            if delim == token::Brace { MacStmtStyle::Braces } else { MacStmtStyle::NoBraces };
+            Some(token::Brace) => MacStmtStyle::Braces,
+            Some(_) => MacStmtStyle::NoBraces,
+            None => unreachable!(),
+        };
 
         let mac = MacCall { path, args, prior_type_ascription: self.last_type_ascription };
 
-        let kind =
+        let kind = if (style == MacStmtStyle::Braces
-            if (delim == token::Brace && self.token != token::Dot && self.token != token::Question)
+            && self.token != token::Dot
+            && self.token != token::Question)
             || self.token == token::Semi
             || self.token == token::Eof
         {

src/tools/rustfmt/src/expr.rs

@@ -1325,7 +1325,7 @@ pub(crate) fn can_be_overflowed_expr(
         }
         ast::ExprKind::MacCall(ref mac) => {
             match (
-                rustc_ast::ast::MacDelimiter::from_token(mac.args.delim()),
+                rustc_ast::ast::MacDelimiter::from_token(mac.args.delim().unwrap()),
                 context.config.overflow_delimited_expr(),
             ) {
                 (Some(ast::MacDelimiter::Bracket), true)