Stabilize param_attrs in Rust 1.39.0

Author: c410-f3r

src/doc/unstable-book/src/language-features/param-attrs.md

@@ -243,6 +243,8 @@ declare_features! (
     (accepted, async_await, "1.39.0", Some(50547), None),
     /// Allows mixing bind-by-move in patterns and references to those identifiers in guards.
     (accepted, bind_by_move_pattern_guards, "1.39.0", Some(15287), None),
+    /// Allows attributes in formal function parameters.
+    (accepted, param_attrs, "1.39.0", Some(60406), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features

src/libsyntax/feature_gate/accepted.rs

@@ -489,9 +489,6 @@ declare_features! (
     /// Allows the user of associated type bounds.
     (active, associated_type_bounds, "1.34.0", Some(52662), None),
 
-    /// Attributes on formal function params.
-    (active, param_attrs, "1.36.0", Some(60406), None),
-
     /// Allows calling constructor functions in `const fn`.
     (active, const_constructor, "1.37.0", Some(61456), None),
 

src/libsyntax/feature_gate/active.rs

@@ -892,7 +892,6 @@ pub fn check_crate(krate: &ast::Crate,
         }
     }
 
-    gate_all!(param_attrs, "attributes on function parameters are unstable");
     gate_all!(let_chains, "`let` expressions in this position are experimental");
     gate_all!(async_closure, "async closures are unstable");
     gate_all!(yields, generators, "yield syntax is experimental");

src/libsyntax/feature_gate/check.rs

@@ -19,13 +19,6 @@ const DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG: &str = "an inner attribute is not \
                                                      permitted in this context";
 
 impl<'a> Parser<'a> {
-    crate fn parse_param_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
-        let attrs = self.parse_outer_attributes()?;
-        self.sess.gated_spans.param_attrs.borrow_mut()
-            .extend(attrs.iter().map(|a| a.span));
-        Ok(attrs)
-    }
-
     /// Parses attributes that appear before an item.
     crate fn parse_outer_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
         let mut attrs: Vec<ast::Attribute> = Vec::new();

src/libsyntax/parse/attr.rs

@@ -42,8 +42,6 @@ pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a>>;
 /// used and should be feature gated accordingly in `check_crate`.
 #[derive(Default)]
 pub struct GatedSpans {
-    /// Spans collected for gating `param_attrs`, e.g. `fn foo(#[attr] x: u8) {}`.
-    pub param_attrs: Lock<Vec<Span>>,
     /// Spans collected for gating `let_chains`, e.g. `if a && let b = c {}`.
     pub let_chains: Lock<Vec<Span>>,
     /// Spans collected for gating `async_closure`, e.g. `async || ..`.

src/libsyntax/parse/mod.rs

@@ -979,7 +979,7 @@ impl<'a> Parser<'a> {
         is_name_required: impl Fn(&token::Token) -> bool,
     ) -> PResult<'a, Param> {
         let lo = self.token.span;
-        let attrs = self.parse_param_attributes()?;
+        let attrs = self.parse_outer_attributes()?;
         if let Some(mut param) = self.parse_self_param()? {
             param.attrs = attrs.into();
             return self.recover_bad_self_param(param, is_trait_item);
@@ -1362,7 +1362,7 @@ impl<'a> Parser<'a> {
     /// Returns the parsed optional self parameter with attributes and whether a self
     /// shortcut was used.
     fn parse_self_parameter_with_attrs(&mut self) -> PResult<'a, Option<Param>> {
-        let attrs = self.parse_param_attributes()?;
+        let attrs = self.parse_outer_attributes()?;
         let param_opt = self.parse_self_param()?;
         Ok(param_opt.map(|mut param| {
             param.attrs = attrs.into();

src/libsyntax/parse/parser.rs

@@ -1176,7 +1176,7 @@ impl<'a> Parser<'a> {
     /// Parses a parameter in a closure header (e.g., `|arg, arg|`).
     fn parse_fn_block_param(&mut self) -> PResult<'a, Param> {
         let lo = self.token.span;
-        let attrs = self.parse_param_attributes()?;
+        let attrs = self.parse_outer_attributes()?;
         let pat = self.parse_pat(PARAM_EXPECTED)?;
         let t = if self.eat(&token::Colon) {
             self.parse_ty()?

src/libsyntax/parse/parser/expr.rs

@@ -3,7 +3,7 @@
 // Exercise the unused_mut attribute in some positive and negative cases
 
 #![deny(unused_mut)]
-#![feature(async_closure, param_attrs)]
+#![feature(async_closure)]
 
 async fn baz_async(
     mut a: i32,

src/test/ui/lint/lint-unused-mut-variables.rs

@@ -1,7 +1,7 @@
 // compile-flags: --cfg something
 // edition:2018
 
-#![feature(async_closure, param_attrs)]
+#![feature(async_closure)]
 #![deny(unused_variables)]
 
 async fn foo_async(

src/test/ui/lint/lint-unused-variables.rs

@@ -2,14 +2,10 @@ pub fn f(
     /// Comment
     //~^ ERROR documentation comments cannot be applied to function parameters
     //~| NOTE doc comments are not allowed here
-    //~| ERROR attributes on function parameters are unstable
-    //~| NOTE https://github.com/rust-lang/rust/issues/60406
     id: u8,
     /// Other
     //~^ ERROR documentation comments cannot be applied to function parameters
     //~| NOTE doc comments are not allowed here
-    //~| ERROR attributes on function parameters are unstable
-    //~| NOTE https://github.com/rust-lang/rust/issues/60406
     a: u8,
 ) {}
 

src/test/ui/parser/fn-arg-doc-comment.rs

@@ -1,5 +1,5 @@
 error: attributes cannot be applied to a function parameter's type
-  --> $DIR/fn-arg-doc-comment.rs:16:12
+  --> $DIR/fn-arg-doc-comment.rs:12:12
    |
 LL | fn bar(id: #[allow(dead_code)] i32) {}
    |            ^^^^^^^^^^^^^^^^^^^ attributes are not allowed here
@@ -11,31 +11,13 @@ LL |     /// Comment
    |     ^^^^^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/fn-arg-doc-comment.rs:8:5
+  --> $DIR/fn-arg-doc-comment.rs:6:5
    |
 LL |     /// Other
    |     ^^^^^^^^^ doc comments are not allowed here
 
-error[E0658]: attributes on function parameters are unstable
-  --> $DIR/fn-arg-doc-comment.rs:2:5
-   |
-LL |     /// Comment
-   |     ^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/60406
-   = help: add `#![feature(param_attrs)]` to the crate attributes to enable
-
-error[E0658]: attributes on function parameters are unstable
-  --> $DIR/fn-arg-doc-comment.rs:8:5
-   |
-LL |     /// Other
-   |     ^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/60406
-   = help: add `#![feature(param_attrs)]` to the crate attributes to enable
-
 error[E0308]: mismatched types
-  --> $DIR/fn-arg-doc-comment.rs:22:7
+  --> $DIR/fn-arg-doc-comment.rs:18:7
    |
 LL |     f("", "");
    |       ^^ expected u8, found reference
@@ -44,7 +26,7 @@ LL |     f("", "");
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/fn-arg-doc-comment.rs:22:11
+  --> $DIR/fn-arg-doc-comment.rs:18:11
    |
 LL |     f("", "");
    |           ^^ expected u8, found reference
@@ -53,15 +35,14 @@ LL |     f("", "");
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/fn-arg-doc-comment.rs:29:9
+  --> $DIR/fn-arg-doc-comment.rs:25:9
    |
 LL |     bar("");
    |         ^^ expected i32, found reference
    |
    = note: expected type `i32`
               found type `&'static str`
 
-error: aborting due to 8 previous errors
+error: aborting due to 6 previous errors
 
-Some errors have detailed explanations: E0308, E0658.
-For more information about an error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0308`.

src/test/ui/parser/fn-arg-doc-comment.stderr

@@ -1,7 +1,5 @@
 // edition:2018
 
-#![feature(param_attrs)]
-
 trait Trait2015 { fn foo(#[allow(C)] i32); }
 //~^ ERROR expected one of `:`, `@`, or `|`, found `)`
 

src/test/ui/rfc-2565-param-attrs/param-attrs-2018.rs

@@ -1,5 +1,5 @@
 error: expected one of `:`, `@`, or `|`, found `)`
-  --> $DIR/param-attrs-2018.rs:5:41
+  --> $DIR/param-attrs-2018.rs:3:41
    |
 LL | trait Trait2015 { fn foo(#[allow(C)] i32); }
    |                                         ^ expected one of `:`, `@`, or `|` here

src/test/ui/rfc-2565-param-attrs/param-attrs-2018.stderr

@@ -2,7 +2,6 @@
 // compile-flags: --cfg something
 
 #![deny(unused_mut)]
-#![feature(param_attrs)]
 
 extern "C" {
     fn ffi(

src/test/ui/rfc-2565-param-attrs/param-attrs-allowed.rs

@@ -1,5 +1,3 @@
-#![feature(param_attrs)]
-
 extern "C" {
     fn ffi(
         /// Foo