Rollup merge of #119062 - compiler-errors:asm-in-let-else, r=davidtwco,est31

Deny braced macro invocations in let-else

Fixes #119057

Pending T-lang decision

cc `@dtolnay`

compiler/rustc_ast/src/util/classify.rs

@@ -2,7 +2,7 @@
 
 // Predicates on exprs and stmts that the pretty-printer and parser use
 
-use crate::ast;
+use crate::{ast, token::Delimiter};
 
 /// Does this expression require a semicolon to be treated
 /// as a statement? The negation of this: 'can this expression
@@ -59,8 +59,12 @@ pub fn expr_trailing_brace(mut expr: &ast::Expr) -> Option<&ast::Expr> {
             | While(..)
             | ConstBlock(_) => break Some(expr),
 
-            // FIXME: These can end in `}`, but changing these would break stable code.
-            InlineAsm(_) | OffsetOf(_, _) | MacCall(_) | IncludedBytes(_) | FormatArgs(_) => {
+            MacCall(mac) => {
+                break (mac.args.delim == Delimiter::Brace).then_some(expr);
+            }
+
+            InlineAsm(_) | OffsetOf(_, _) | IncludedBytes(_) | FormatArgs(_) => {
+                // These should have been denied pre-expansion.
                 break None;
             }