"(const: unstable)" for stable-but-const-unstable

3 files changed, 33 insertions, 9 deletions

diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 62d3c142eeb..16df17372b0 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -42,7 +42,7 @@ use std::str;
 use std::string::ToString;
 
 use rustc_ast_pretty::pprust;
-use rustc_attr::{Deprecation, StabilityLevel};
+use rustc_attr::{ConstStability, Deprecation, StabilityLevel};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::CtorKind;
@@ -826,20 +826,42 @@ fn assoc_type(
 fn render_stability_since_raw(
     w: &mut Buffer,
     ver: Option<&str>,
-    const_ver: Option<&str>,
+    const_stability: Option<&ConstStability>,
     containing_ver: Option<&str>,
     containing_const_ver: Option<&str>,
 ) {
     let ver = ver.filter(|inner| !inner.is_empty());
-    let const_ver = const_ver.filter(|inner| !inner.is_empty());
 
-    match (ver, const_ver) {
-        (Some(v), Some(cv)) if const_ver != containing_const_ver => {
+    match (ver, const_stability) {
+        (Some(v), Some(ConstStability { level: StabilityLevel::Stable { since }, .. }))
+            if Some(since.as_str()).as_deref() != containing_const_ver =>
+        {
             write!(
                 w,
                 "<span class=\"since\" title=\"Stable since Rust version {0}, const since {1}\">{0} (const: {1})</span>",
-                v, cv
+                v,
+                since.as_str()
+            );
+        }
+        (
+            Some(v),
+            Some(ConstStability { level: StabilityLevel::Unstable { issue, .. }, feature, .. }),
+        ) => {
+            write!(
+                w,
+                "<span class=\"since\" title=\"Stable since Rust version {0}, const unstable\">{0} (const: ",
+                v
             );
+            if let Some(n) = issue {
+                write!(
+                    w,
+                    "<a href=\"https://github.com/rust-lang/rust/issues/{}\" title=\"Tracking issue for {}\">unstable</a>",
+                    n, feature
+                );
+            } else {
+                write!(w, "unstable");
+            }
+            write!(w, ")</span>");
         }
         (Some(v), _) if ver != containing_ver => {
             write!(
@@ -1583,7 +1605,7 @@ fn render_rightside(
     render_stability_since_raw(
         w,
         item.stable_since(tcx).as_deref(),
-        item.const_stable_since(tcx).as_deref(),
+        item.const_stability(tcx),
         containing_item.stable_since(tcx).as_deref(),
         containing_item.const_stable_since(tcx).as_deref(),
     );
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 48cbd94ccab..1340040fa8f 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -94,7 +94,7 @@ pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut Buffer,
     render_stability_since_raw(
         buf,
         item.stable_since(cx.tcx()).as_deref(),
-        item.const_stable_since(cx.tcx()).as_deref(),
+        item.const_stability(cx.tcx()),
         None,
         None,
     );
@@ -1291,7 +1291,7 @@ fn render_stability_since(
     render_stability_since_raw(
         w,
         item.stable_since(tcx).as_deref(),
-        item.const_stable_since(tcx).as_deref(),
+        item.const_stability(tcx),
         containing_item.stable_since(tcx).as_deref(),
         containing_item.const_stable_since(tcx).as_deref(),
     )
diff --git a/src/test/rustdoc/const-display.rs b/src/test/rustdoc/const-display.rs
index 2761f92ef57..41a511f7165 100644
--- a/src/test/rustdoc/const-display.rs
+++ b/src/test/rustdoc/const-display.rs
@@ -8,6 +8,7 @@
 #![feature(staged_api)]
 
 // @has 'foo/fn.foo.html' '//pre' 'pub unsafe fn foo() -> u32'
+// @has - '//span[@class="since"]' '1.0.0 (const: unstable)'
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature="foo", issue = "none")]
 pub const unsafe fn foo() -> u32 { 42 }
@@ -39,6 +40,7 @@ pub struct Foo;
 
 impl Foo {
     // @has 'foo/struct.Foo.html' '//div[@id="method.gated"]/code' 'pub unsafe fn gated() -> u32'
+    // @has - '//span[@class="since"]' '1.0.0 (const: unstable)'
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_const_unstable(feature="foo", issue = "none")]
     pub const unsafe fn gated() -> u32 { 42 }