Switch proc-macros to default to 2024 edition

This changes the default edition with the intent to reduce more
boilerplate, and to use modern Rust for these proc-macro helpers. For
the rare case where the edition of the proc-macro matters, it can be set
explicitly (which seems good to me to be explicit).

Author: ehuss

src/tools/compiletest/src/header.rs

@@ -199,6 +199,8 @@ pub struct TestProps {
     /// Build and use `minicore` as `core` stub for `no_core` tests in cross-compilation scenarios
     /// that don't otherwise want/need `-Z build-std`.
     pub add_core_stubs: bool,
+    /// The edition for this test.
+    pub edition: Option<String>,
 }
 
 mod directives {
@@ -247,6 +249,7 @@ mod directives {
     pub const ADD_CORE_STUBS: &'static str = "add-core-stubs";
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
+    pub const EDITION: &'static str = "edition";
 }
 
 impl TestProps {
@@ -302,6 +305,7 @@ impl TestProps {
             no_auto_check_cfg: false,
             has_enzyme: false,
             add_core_stubs: false,
+            edition: None,
         }
     }
 
@@ -335,7 +339,6 @@ impl TestProps {
     /// `//@[foo]`), then the property is ignored unless `test_revision` is
     /// `Some("foo")`.
     fn load_from(&mut self, testfile: &Path, test_revision: Option<&str>, config: &Config) {
-        let mut has_edition = false;
         if !testfile.is_dir() {
             let file = File::open(testfile).unwrap();
 
@@ -389,10 +392,9 @@ impl TestProps {
                         panic!("`compiler-flags` directive should be spelled `compile-flags`");
                     }
 
-                    if let Some(edition) = config.parse_edition(ln) {
-                        self.compile_flags.push(format!("--edition={}", edition.trim()));
-                        has_edition = true;
-                    }
+                    config.set_name_value_directive(ln, EDITION, &mut self.edition, |r| {
+                        r.trim().to_string()
+                    });
 
                     config.parse_and_update_revisions(testfile, ln, &mut self.revisions);
 
@@ -601,10 +603,6 @@ impl TestProps {
                 }
             }
         }
-
-        if let (Some(edition), false) = (&config.edition, has_edition) {
-            self.compile_flags.push(format!("--edition={}", edition));
-        }
     }
 
     fn update_fail_mode(&mut self, ln: &str, config: &Config) {
@@ -1027,10 +1025,6 @@ impl Config {
         None
     }
 
-    fn parse_edition(&self, line: &str) -> Option<String> {
-        self.parse_name_value_directive(line, "edition")
-    }
-
     fn set_name_directive(&self, line: &str, directive: &str, value: &mut bool) {
         match value {
             true => {

src/tools/compiletest/src/runtest.rs

@@ -428,8 +428,8 @@ impl<'test> TestCx<'test> {
             .arg(&aux_dir)
             .arg("-A")
             .arg("internal_features")
-            .args(&self.props.compile_flags)
             .envs(self.props.rustc_env.clone());
+        self.add_common_args(&mut rustc);
         self.maybe_add_external_args(&mut rustc, &self.config.target_rustcflags);
 
         let src = match read_from {
@@ -534,7 +534,7 @@ impl<'test> TestCx<'test> {
             .arg("internal_features");
         self.set_revision_flags(&mut rustc);
         self.maybe_add_external_args(&mut rustc, &self.config.target_rustcflags);
-        rustc.args(&self.props.compile_flags);
+        self.add_common_args(&mut rustc);
 
         self.compose_and_run_compiler(rustc, Some(src), self.testpaths)
     }
@@ -937,8 +937,8 @@ impl<'test> TestCx<'test> {
             .arg(&self.testpaths.file)
             .arg("-A")
             .arg("internal_features")
-            .args(&self.props.compile_flags)
             .args(&self.props.doc_flags);
+        self.add_common_args(&mut rustdoc);
 
         if self.config.mode == RustdocJson {
             rustdoc.arg("--output-format").arg("json").arg("-Zunstable-options");
@@ -1242,6 +1242,9 @@ impl<'test> TestCx<'test> {
             self.props.from_aux_file(&aux_testpaths.file, self.revision, self.config);
         if aux_type == Some(AuxType::ProcMacro) {
             aux_props.force_host = true;
+            if aux_props.edition.is_none() {
+                aux_props.edition = Some("2024".to_string());
+            }
         }
         let mut aux_dir = aux_dir.to_path_buf();
         if aux_type == Some(AuxType::Bin) {
@@ -1731,7 +1734,7 @@ impl<'test> TestCx<'test> {
             }
         }
 
-        rustc.args(&self.props.compile_flags);
+        self.add_common_args(&mut rustc);
 
         // FIXME(jieyouxu): we should report a fatal error or warning if user wrote `-Cpanic=` with
         // something that's not `abort`, however, by moving this last we should override previous
@@ -1745,6 +1748,13 @@ impl<'test> TestCx<'test> {
         rustc
     }
 
+    fn add_common_args(&self, cmd: &mut Command) {
+        cmd.args(&self.props.compile_flags);
+        if let Some(edition) = &self.props.edition {
+            cmd.args(&["--edition", edition.as_str()]);
+        }
+    }
+
     fn make_exe_name(&self) -> PathBuf {
         // Using a single letter here to keep the path length down for
         // Windows.  Some test names get very long.  rustc creates `rcgu`

tests/codegen/debuginfo-proc-macro/auxiliary/macro_def.rs

@@ -1,4 +1,3 @@
-extern crate proc_macro;
 use proc_macro::*;
 
 #[proc_macro]

tests/incremental/auxiliary/incremental_proc_macro_aux.rs

@@ -1,5 +1,3 @@
-extern crate proc_macro;
-
 use proc_macro::TokenStream;
 
 // Add a function to shift DefIndex of registrar function

tests/incremental/auxiliary/issue-49482-macro-def.rs

@@ -1,7 +1,5 @@
 #![allow(non_snake_case)]
 
-extern crate proc_macro;
-
 macro_rules! proc_macro_expr_impl {
     ($(
         $( #[$attr:meta] )*

tests/incremental/auxiliary/issue-49482-reexport.rs

@@ -1,4 +1,5 @@
 //@ proc-macro: issue-49482-macro-def.rs
+
 #[macro_use]
 extern crate issue_49482_macro_def;
 

tests/incremental/auxiliary/issue-54059.rs

@@ -2,8 +2,6 @@
 
 #![allow(non_snake_case)]
 
-extern crate proc_macro;
-
 macro_rules! proc_macro_tokenstream {
     () => {
         ::proc_macro::TokenStream
@@ -41,6 +39,6 @@ proc_macro_expr_impl! {
 }
 
 #[link(name="rust_test_helpers")]
-extern "C" {
+unsafe extern "C" {
     pub fn rust_dbg_extern_identity_u64(v: u64) -> u64;
 }

tests/incremental/issue-110457-same-span-closures/auxiliary/egui_inspect_derive.rs

@@ -1,5 +1,3 @@
-extern crate proc_macro;
-
 use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
 
 #[proc_macro]

tests/incremental/issue-85197-invalid-span/auxiliary/invalid-span-helper-lib.rs

@@ -1,5 +1,6 @@
 //@ proc-macro: respan.rs
 //@ revisions: rpass1 rpass2
+//@ proc-macro: respan.rs
 
 extern crate respan;
 

tests/incremental/issue-85197-invalid-span/auxiliary/respan.rs

@@ -1,7 +1,5 @@
-extern crate proc_macro;
 use proc_macro::TokenStream;
 
-
 /// Copies the resolution information (the `SyntaxContext`) of the first
 /// token to all other tokens in the stream. Does not recurse into groups.
 #[proc_macro]