Stabilize unrestricted_attribute_tokens

Author: petrochenkov

src/libcore/lib.rs

@@ -123,7 +123,6 @@
 #![feature(abi_unadjusted)]
 #![feature(adx_target_feature)]
 #![feature(maybe_uninit, maybe_uninit_slice, maybe_uninit_array)]
-#![feature(unrestricted_attribute_tokens)]
 #![feature(external_doc)]
 
 #[prelude_import]

src/libsyntax/feature_gate.rs

@@ -21,8 +21,9 @@ use crate::early_buffered_lints::BufferedEarlyLintId;
 use crate::source_map::Spanned;
 use crate::edition::{ALL_EDITIONS, Edition};
 use crate::visit::{self, FnKind, Visitor};
-use crate::parse::ParseSess;
+use crate::parse::{token, ParseSess};
 use crate::symbol::Symbol;
+use crate::tokenstream::TokenTree;
 
 use errors::{DiagnosticBuilder, Handler};
 use rustc_data_structures::fx::FxHashMap;
@@ -431,9 +432,6 @@ declare_features! (
     // Added for testing E0705; perma-unstable.
     (active, test_2018_feature, "1.31.0", Some(0), Some(Edition::Edition2018)),
 
-    // support for arbitrary delimited token streams in non-macro attributes
-    (active, unrestricted_attribute_tokens, "1.30.0", Some(55208), None),
-
     // Allows unsized rvalues at arguments and parameters.
     (active, unsized_locals, "1.30.0", Some(48055), None),
 
@@ -700,6 +698,8 @@ declare_features! (
     (accepted, cfg_target_vendor, "1.33.0", Some(29718), None),
     // `extern crate self as foo;` puts local crate root into extern prelude under name `foo`.
     (accepted, extern_crate_self, "1.34.0", Some(56409), None),
+    // support for arbitrary delimited token streams in non-macro attributes
+    (accepted, unrestricted_attribute_tokens, "1.34.0", Some(55208), None),
 );
 
 // If you change this, please modify `src/doc/unstable-book` as well. You must
@@ -1660,13 +1660,9 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
 
         match BUILTIN_ATTRIBUTES.iter().find(|(name, ..)| attr.path == name) {
             Some(&(name, _, template, _)) => self.check_builtin_attribute(attr, name, template),
-            None => if !self.context.features.unrestricted_attribute_tokens {
-                // Unfortunately, `parse_meta` cannot be called speculatively
-                // because it can report errors by itself, so we have to call it
-                // only if the feature is disabled.
-                if let Err(mut err) = attr.parse_meta(self.context.parse_sess) {
-                    err.help("try enabling `#![feature(unrestricted_attribute_tokens)]`").emit()
-                }
+            None => if let Some(TokenTree::Token(_, token::Eq)) = attr.tokens.trees().next() {
+                // All key-value attributes are restricted to meta-item syntax.
+                attr.parse_meta(self.context.parse_sess).map_err(|mut err| err.emit()).ok();
             }
         }
     }

src/test/run-pass/proc-macro/derive-b.rs

@@ -1,7 +1,5 @@
 // aux-build:derive-b.rs
 
-#![feature(unrestricted_attribute_tokens)]
-
 extern crate derive_b;
 
 #[derive(Debug, PartialEq, derive_b::B, Eq, Copy, Clone)]

src/test/ui/attr-eq-token-tree.rs

@@ -1,4 +1,4 @@
-#![feature(custom_attribute, unrestricted_attribute_tokens)]
+#![feature(custom_attribute)]
 
 #[my_attr = !] //~ ERROR unexpected token: `!`
 fn main() {}

src/test/ui/feature-gates/feature-gate-unrestricted-attribute-tokens.rs

@@ -1,4 +1,2 @@
-#![feature(unrestricted_attribute_tokens)]
-
 #[doc = $not_there] //~ ERROR unexpected token: `$`
 fn main() { }

src/test/ui/feature-gates/feature-gate-unrestricted-attribute-tokens.stderr

@@ -1,5 +1,5 @@
 error: unexpected token: `$`
-  --> $DIR/macro-attribute.rs:3:7
+  --> $DIR/macro-attribute.rs:1:7
    |
 LL | #[doc = $not_there] //~ ERROR unexpected token: `$`
    |       ^

src/test/ui/macros/macro-attribute.rs

@@ -17,8 +17,6 @@ LL |         #[my_attr = $expr] //~ ERROR suffixed literals are not allowed in a
 ...
 LL | check!(-0); // ERROR, see above
    | ----------- in this macro invocation
-   |
-   = help: try enabling `#![feature(unrestricted_attribute_tokens)]`
 
 error: unexpected token: `0 + 0`
   --> $DIR/malformed-interpolated.rs:5:19
@@ -28,8 +26,6 @@ LL |         #[my_attr = $expr] //~ ERROR suffixed literals are not allowed in a
 ...
 LL | check!(0 + 0); // ERROR, see above
    | -------------- in this macro invocation
-   |
-   = help: try enabling `#![feature(unrestricted_attribute_tokens)]`
 
 error: aborting due to 3 previous errors
 

src/test/ui/macros/macro-attribute.stderr

@@ -1,5 +1,4 @@
 #![feature(marker_trait_attr)]
-#![feature(unrestricted_attribute_tokens)]
 
 #[marker(always)]
 trait Marker1 {}
@@ -9,8 +8,8 @@ trait Marker1 {}
 trait Marker2 {}
 //~^^ ERROR attribute must be of the form
 
-#[marker(key = value)]
+#[marker(key = "value")]
 trait Marker3 {}
-//~^^ ERROR expected unsuffixed literal or identifier, found value
+//~^^ ERROR attribute must be of the form `#[marker]`
 
 fn main() {}