Auto merge of #54850 - mcr431:fix-54707-trait-function-from-macro, r=nikomatsakis

Fix #54707 - parse_trait_item_ now handles interpolated blocks as function body decls

Fix #54707 - parse_trait_item_ now handles interpolated blocks as function body decls

Previously parsing trait items only handled opening brace token and semicolon, I added a branch to the match statement that will also handle interpolated blocks.

src/test/run-pass/macros/macro-as-fn-body.rs

@@ -0,0 +1,42 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+//
+// run-pass
+//
+// Description - ensure Interpolated blocks can act as valid function bodies
+// Covered cases: free functions, struct methods, and default trait functions
+
+macro_rules! def_fn {
+    ($body:block) => {
+        fn bar() $body
+    }
+}
+
+trait Foo {
+    def_fn!({ println!("foo"); });
+}
+
+struct Baz {}
+
+impl Foo for Baz {}
+
+struct Qux {}
+
+impl Qux {
+    def_fn!({ println!("qux"); });
+}
+
+def_fn!({ println!("quux"); });
+
+pub fn main() {
+    Baz::bar();
+    Qux::bar();
+    bar();
+}