Auto merge of #48851 - petrochenkov:genparattr, r=nikomatsakis

Stabilize attributes on generic parameters

Closes #48848

Author: bors

Diff for: src/liballoc/lib.rs

@@ -97,7 +97,7 @@
 #![feature(fmt_internals)]
 #![feature(from_ref)]
 #![feature(fundamental)]
-#![feature(generic_param_attrs)]
+#![cfg_attr(stage0, feature(generic_param_attrs))]
 #![cfg_attr(stage0, feature(i128_type))]
 #![feature(lang_items)]
 #![feature(needs_allocator)]

Diff for: src/libarena/lib.rs

@@ -27,7 +27,7 @@
 #![feature(alloc)]
 #![feature(core_intrinsics)]
 #![feature(dropck_eyepatch)]
-#![feature(generic_param_attrs)]
+#![cfg_attr(stage0, feature(generic_param_attrs))]
 #![cfg_attr(test, feature(test))]
 
 #![allow(deprecated)]

Diff for: src/librustc_typeck/diagnostics.rs

@@ -3784,7 +3784,6 @@ that impl must be declared as an `unsafe impl.
 Erroneous code example:
 
 ```compile_fail,E0569
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 struct Foo<X>(X);

Diff for: src/libstd/lib.rs

@@ -266,7 +266,7 @@
 #![feature(float_from_str_radix)]
 #![feature(fn_traits)]
 #![feature(fnbox)]
-#![feature(generic_param_attrs)]
+#![cfg_attr(stage0, feature(generic_param_attrs))]
 #![feature(hashmap_internals)]
 #![feature(heap_api)]
 #![cfg_attr(stage0, feature(i128_type, i128))]

Diff for: src/libsyntax/feature_gate.rs

@@ -288,9 +288,6 @@ declare_features! (
     // rustc internal
     (active, compiler_builtins, "1.13.0", None, None),
 
-    // Allows attributes on lifetime/type formal parameters in generics (RFC 1327)
-    (active, generic_param_attrs, "1.11.0", Some(34761), None),
-
     // Allows #[link(..., cfg(..))]
     (active, link_cfg, "1.14.0", Some(37406), None),
 
@@ -566,6 +563,8 @@ declare_features! (
     (accepted, match_default_bindings, "1.26.0", Some(42640), None),
     // allow `'_` placeholder lifetimes
     (accepted, underscore_lifetimes, "1.26.0", Some(44524), None),
+    // Allows attributes on lifetime/type formal parameters in generics (RFC 1327)
+    (accepted, generic_param_attrs, "1.26.0", Some(48848), None),
 );
 
 // If you change this, please modify src/doc/unstable-book as well. You must
@@ -1775,21 +1774,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
         }
         visit::walk_vis(self, vis);
     }
-
-    fn visit_generic_param(&mut self, param: &'a ast::GenericParam) {
-        let (attrs, explain) = match *param {
-            ast::GenericParam::Lifetime(ref ld) =>
-                (&ld.attrs, "attributes on lifetime bindings are experimental"),
-            ast::GenericParam::Type(ref t) =>
-                (&t.attrs, "attributes on type parameter bindings are experimental"),
-        };
-
-        if !attrs.is_empty() {
-            gate_feature_post!(&self, generic_param_attrs, attrs[0].span, explain);
-        }
-
-        visit::walk_generic_param(self, param)
-    }
 }
 
 pub fn get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute],

Diff for: src/test/compile-fail/attrs-with-no-formal-in-generics-1.rs

@@ -12,8 +12,7 @@
 // `#[oops]` is left dangling (that is, it is unattached, with no
 // formal binding following it).
 
-#![feature(generic_param_attrs, rustc_attrs)]
-#![allow(dead_code)]
+#![feature(rustc_attrs)]
 
 struct RefIntPair<'a, 'b>(&'a u32, &'b u32);
 

Diff for: src/test/compile-fail/attrs-with-no-formal-in-generics-2.rs

@@ -12,8 +12,7 @@
 // `#[oops]` is left dangling (that is, it is unattached, with no
 // formal binding following it).
 
-#![feature(generic_param_attrs, rustc_attrs)]
-#![allow(dead_code)]
+#![feature(rustc_attrs)]
 
 struct RefAny<'a, T>(&'a T);
 

Diff for: src/test/compile-fail/synthetic-param.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs, rustc_attrs)]
+#![feature(rustc_attrs)]
 
 fn func<#[rustc_synthetic] T>(_: T) {}
 

Diff for: src/test/mir-opt/end_region_destruction_extents_1.rs

@@ -14,7 +14,6 @@
 // A scenario with significant destruction code extents (which have
 // suffix "dce" in current `-Z identify_regions` rendering).
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 fn main() {

Diff for: src/test/run-pass/attr-on-generic-formals.rs

@@ -17,7 +17,7 @@
 // using `rustc_attrs` feature. There is a separate compile-fail/ test
 // ensuring that the attribute feature-gating works in this context.)
 
-#![feature(generic_param_attrs, rustc_attrs)]
+#![feature(rustc_attrs)]
 #![allow(dead_code)]
 
 struct StLt<#[rustc_lt_struct] 'a>(&'a u32);

Diff for: src/test/run-pass/auxiliary/dropck_eyepatch_extern_crate.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // The point of this test is to illustrate that the `#[may_dangle]`

Diff for: src/test/run-pass/dropck-eyepatch-reorder.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // The point of this test is to test uses of `#[may_dangle]` attribute

Diff for: src/test/run-pass/dropck-eyepatch.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // The point of this test is to illustrate that the `#[may_dangle]`

Diff for: src/test/ui/dropck/auxiliary/dropck_eyepatch_extern_crate.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // This is a support file for ../dropck-eyepatch-extern-crate.rs

Diff for: src/test/ui/dropck/dropck-eyepatch-implies-unsafe-impl.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // This test ensures that a use of `#[may_dangle]` is rejected if

Diff for: src/test/ui/dropck/dropck-eyepatch-implies-unsafe-impl.stderr

@@ -1,5 +1,5 @@
 error[E0569]: requires an `unsafe impl` declaration due to `#[may_dangle]` attribute
-  --> $DIR/dropck-eyepatch-implies-unsafe-impl.rs:32:1
+  --> $DIR/dropck-eyepatch-implies-unsafe-impl.rs:31:1
    |
 LL | / impl<#[may_dangle] A, B: fmt::Debug> Drop for Pt<A, B> {
 LL | |     //~^ ERROR requires an `unsafe impl` declaration due to `#[may_dangle]` attribute
@@ -10,7 +10,7 @@ LL | | }
    | |_^
 
 error[E0569]: requires an `unsafe impl` declaration due to `#[may_dangle]` attribute
-  --> $DIR/dropck-eyepatch-implies-unsafe-impl.rs:38:1
+  --> $DIR/dropck-eyepatch-implies-unsafe-impl.rs:37:1
    |
 LL | / impl<#[may_dangle] 'a, 'b, B: fmt::Debug> Drop for Pr<'a, 'b, B> {
 LL | |     //~^ ERROR requires an `unsafe impl` declaration due to `#[may_dangle]` attribute

Diff for: src/test/ui/dropck/dropck-eyepatch-reorder.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // The point of this test is to test uses of `#[may_dangle]` attribute

Diff for: src/test/ui/dropck/dropck-eyepatch-reorder.stderr

@@ -1,5 +1,5 @@
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch-reorder.rs:57:20
+  --> $DIR/dropck-eyepatch-reorder.rs:56:20
    |
 LL |     dt = Dt("dt", &c);
    |                    ^ borrowed value does not live long enough
@@ -10,7 +10,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch-reorder.rs:59:20
+  --> $DIR/dropck-eyepatch-reorder.rs:58:20
    |
 LL |     dr = Dr("dr", &c);
    |                    ^ borrowed value does not live long enough
@@ -21,7 +21,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch-reorder.rs:67:29
+  --> $DIR/dropck-eyepatch-reorder.rs:66:29
    |
 LL |     pt = Pt("pt", &c_long, &c);
    |                             ^ borrowed value does not live long enough
@@ -32,7 +32,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch-reorder.rs:69:29
+  --> $DIR/dropck-eyepatch-reorder.rs:68:29
    |
 LL |     pr = Pr("pr", &c_long, &c);
    |                             ^ borrowed value does not live long enough

Diff for: src/test/ui/dropck/dropck-eyepatch.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(generic_param_attrs)]
 #![feature(dropck_eyepatch)]
 
 // The point of this test is to illustrate that the `#[may_dangle]`

Diff for: src/test/ui/dropck/dropck-eyepatch.stderr

@@ -1,5 +1,5 @@
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch.rs:80:20
+  --> $DIR/dropck-eyepatch.rs:79:20
    |
 LL |     dt = Dt("dt", &c);
    |                    ^ borrowed value does not live long enough
@@ -10,7 +10,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch.rs:82:20
+  --> $DIR/dropck-eyepatch.rs:81:20
    |
 LL |     dr = Dr("dr", &c);
    |                    ^ borrowed value does not live long enough
@@ -21,7 +21,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch.rs:90:29
+  --> $DIR/dropck-eyepatch.rs:89:29
    |
 LL |     pt = Pt("pt", &c_long, &c);
    |                             ^ borrowed value does not live long enough
@@ -32,7 +32,7 @@ LL | }
    = note: values in a scope are dropped in the opposite order they are created
 
 error[E0597]: `c` does not live long enough
-  --> $DIR/dropck-eyepatch.rs:92:29
+  --> $DIR/dropck-eyepatch.rs:91:29
    |
 LL |     pr = Pr("pr", &c_long, &c);
    |                             ^ borrowed value does not live long enough

Diff for: src/test/ui/feature-gate-custom_attribute2.rs

@@ -10,16 +10,9 @@
 
 // This test ensures that attributes on formals in generic parameter
 // lists are included when we are checking for unstable attributes.
-//
-// Note that feature(generic_param_attrs) *is* enabled here. We are
-// checking feature-gating of the attributes themselves, not the
-// capability to parse such attributes in that context.
 
 // gate-test-custom_attribute
 
-#![feature(generic_param_attrs)]
-#![allow(dead_code)]
-
 struct StLt<#[lt_struct] 'a>(&'a u32);
 //~^ ERROR The attribute `lt_struct` is currently unknown to the compiler
 struct StTy<#[ty_struct] I>(I);