rustc_expand: Mark inner #![test] attributes as soft-unstable

Author: petrochenkov

compiler/rustc_expand/src/expand.rs

@@ -22,7 +22,7 @@ use rustc_errors::{struct_span_err, Applicability, PResult};
 use rustc_feature::Features;
 use rustc_parse::parser::{AttemptLocalParseRecovery, Parser};
 use rustc_parse::validate_attr;
-use rustc_session::lint::builtin::UNUSED_DOC_COMMENTS;
+use rustc_session::lint::builtin::{SOFT_UNSTABLE, UNUSED_DOC_COMMENTS};
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::{feature_err, ParseSess};
 use rustc_session::Limit;
@@ -1064,17 +1064,24 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
             })
             .map(|i| attrs.remove(i));
         if let Some(attr) = &attr {
-            if !self.cx.ecfg.custom_inner_attributes()
-                && attr.style == ast::AttrStyle::Inner
-                && !attr.has_name(sym::test)
-            {
-                feature_err(
-                    &self.cx.sess.parse_sess,
-                    sym::custom_inner_attributes,
-                    attr.span,
-                    "non-builtin inner attributes are unstable",
-                )
-                .emit();
+            if attr.style == ast::AttrStyle::Inner && !self.cx.ecfg.custom_inner_attributes() {
+                let msg = "non-builtin inner attributes are unstable";
+                if attr.has_name(sym::test) {
+                    self.cx.sess.parse_sess.buffer_lint(
+                        SOFT_UNSTABLE,
+                        attr.span,
+                        ast::CRATE_NODE_ID,
+                        msg,
+                    );
+                } else {
+                    feature_err(
+                        &self.cx.sess.parse_sess,
+                        sym::custom_inner_attributes,
+                        attr.span,
+                        msg,
+                    )
+                    .emit();
+                }
             }
         }
         attr

library/std/src/num/tests.rs

@@ -75,8 +75,8 @@ fn test_checked_mul() {
 
 macro_rules! test_is_power_of_two {
     ($test_name:ident, $T:ident) => {
+        #[test]
         fn $test_name() {
-            #![test]
             assert_eq!((0 as $T).is_power_of_two(), false);
             assert_eq!((1 as $T).is_power_of_two(), true);
             assert_eq!((2 as $T).is_power_of_two(), true);
@@ -96,8 +96,8 @@ test_is_power_of_two! { test_is_power_of_two_uint, usize }
 
 macro_rules! test_next_power_of_two {
     ($test_name:ident, $T:ident) => {
+        #[test]
         fn $test_name() {
-            #![test]
             assert_eq!((0 as $T).next_power_of_two(), 1);
             let mut next_power = 1;
             for i in 1 as $T..40 {
@@ -118,8 +118,8 @@ test_next_power_of_two! { test_next_power_of_two_uint, usize }
 
 macro_rules! test_checked_next_power_of_two {
     ($test_name:ident, $T:ident) => {
+        #[test]
         fn $test_name() {
-            #![test]
             assert_eq!((0 as $T).checked_next_power_of_two(), Some(1));
             let smax = $T::MAX >> 1;
             assert_eq!(smax.checked_next_power_of_two(), Some(smax + 1));

src/test/ui/feature-gate/issue-43106-gating-of-test.rs

@@ -1,5 +1,6 @@
 // The non-crate level cases are in issue-43106-gating-of-builtin-attrs.rs.
 
+#![allow(soft_unstable)]
 #![test                    = "4200"]
 //~^ ERROR cannot determine resolution for the attribute macro `test`
 

src/test/ui/feature-gate/issue-43106-gating-of-test.stderr

@@ -1,5 +1,5 @@
 error: cannot determine resolution for the attribute macro `test`
-  --> $DIR/issue-43106-gating-of-test.rs:3:4
+  --> $DIR/issue-43106-gating-of-test.rs:4:4
    |
 LL | #![test                    = "4200"]
    |    ^^^^

src/test/ui/issues/issue-28134.rs

@@ -1,3 +1,4 @@
 // compile-flags: --test
 
+#![allow(soft_unstable)]
 #![test] //~ ERROR cannot determine resolution for the attribute macro `test`

src/test/ui/issues/issue-28134.stderr

@@ -1,5 +1,5 @@
 error: cannot determine resolution for the attribute macro `test`
-  --> $DIR/issue-28134.rs:3:4
+  --> $DIR/issue-28134.rs:4:4
    |
 LL | #![test]
    |    ^^^^

src/test/ui/proc-macro/proc-macro-gates.rs

@@ -45,4 +45,9 @@ fn attrs() {
     //~^ ERROR: custom attributes cannot be applied to expressions
 }
 
+fn test_case() {
+    #![test] //~ ERROR non-builtin inner attributes are unstable
+             //~| WARN this was previously accepted
+}
+
 fn main() {}

src/test/ui/proc-macro/proc-macro-gates.stderr

@@ -76,6 +76,16 @@ LL |     let _x = #[identity_attr] println!();
    = note: see issue #54727 <https://github.com/rust-lang/rust/issues/54727> for more information
    = help: add `#![feature(proc_macro_hygiene)]` to the crate attributes to enable
 
-error: aborting due to 9 previous errors
+error: non-builtin inner attributes are unstable
+  --> $DIR/proc-macro-gates.rs:49:5
+   |
+LL |     #![test]
+   |     ^^^^^^^^
+   |
+   = note: `#[deny(soft_unstable)]` on by default
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #64266 <https://github.com/rust-lang/rust/issues/64266>
+
+error: aborting due to 10 previous errors
 
 For more information about this error, try `rustc --explain E0658`.