Hint user to update nightly on ICEs produced from outdated nightly

compiler/rustc_driver_impl/Cargo.toml

@@ -50,7 +50,7 @@ rustc_trait_selection = { path = "../rustc_trait_selection" }
 rustc_ty_utils = { path = "../rustc_ty_utils" }
 serde_json = "1.0.59"
 shlex = "1.0"
-time = { version = "0.3", default-features = false, features = ["alloc", "formatting"] }
+time = { version = "0.3", default-features = false, features = ["alloc", "formatting", "parsing", "macros"] }
 tracing = { version = "0.1.35" }
 # tidy-alphabetical-end
 

compiler/rustc_driver_impl/messages.ftl

@@ -1,6 +1,14 @@
 driver_impl_ice = the compiler unexpectedly panicked. this is a bug.
 driver_impl_ice_bug_report = we would appreciate a bug report: {$bug_report_url}
 driver_impl_ice_bug_report_internal_feature = using internal features is not supported and expected to cause internal compiler errors when used incorrectly
+driver_impl_ice_bug_report_internal_feature_outdated =
+    using internal features is not supported and expected to cause internal compiler errors when used incorrectly
+    .outdated = it seems this '{$version}' is outdated, a newer nightly should have been released in the mean time
+    .update = please consider running `rustup update nightly` to update the nightly channel and check if this problem still persists
+driver_impl_ice_bug_report_outdated =
+    it seems this '{$version}' is outdated, a newer nightly should have been released in the mean time
+    .update = please consider running `rustup update nightly` to update the nightly channel and check if this problem still persists
+    .url = we would appreciate a bug report: {$bug_report_url}
 driver_impl_ice_exclude_cargo_defaults = some of the compiler flags provided by cargo are hidden
 
 driver_impl_ice_flags = compiler flags: {$flags}

compiler/rustc_driver_impl/src/lib.rs

@@ -57,7 +57,7 @@ use std::str;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, OnceLock};
 use std::time::{Instant, SystemTime};
-use time::OffsetDateTime;
+use time::{Date, OffsetDateTime, Time};
 
 #[allow(unused_macros)]
 macro do_not_use_print($($t:tt)*) {
@@ -1370,6 +1370,9 @@ pub fn install_ice_hook(
     using_internal_features
 }
 
+const DATE_FORMAT: &[time::format_description::FormatItem<'static>] =
+    &time::macros::format_description!("[year]-[month]-[day]");
+
 /// Prints the ICE message, including query stack, but without backtrace.
 ///
 /// The message will point the user at `bug_report_url` to report the ICE.
@@ -1398,10 +1401,41 @@ fn report_ice(
         dcx.emit_err(session_diagnostics::Ice);
     }
 
-    if using_internal_features.load(std::sync::atomic::Ordering::Relaxed) {
-        dcx.emit_note(session_diagnostics::IceBugReportInternalFeature);
+    use time::ext::NumericalDuration;
+
+    // Try to hint user to update nightly if applicable when reporting an ICE.
+    // Attempt to calculate when current version was released, and add 12 hours
+    // as buffer. If the current version's release timestamp is older than
+    // the system's current time + 24 hours + 12 hours buffer if we're on
+    // nightly.
+    if let Some("nightly") = option_env!("CFG_RELEASE_CHANNEL")
+        && let Some(version) = option_env!("CFG_VERSION")
+        && let Some(ver_date_str) = option_env!("CFG_VER_DATE")
+        && let Ok(ver_date) = Date::parse(&ver_date_str, DATE_FORMAT)
+        && let ver_datetime = OffsetDateTime::new_utc(ver_date, Time::MIDNIGHT)
+        && let system_datetime = OffsetDateTime::from(SystemTime::now())
+        && system_datetime.checked_sub(36.hours()).is_some_and(|d| d > ver_datetime)
+    {
+        if using_internal_features.load(std::sync::atomic::Ordering::Relaxed) {
+            dcx.emit_note(session_diagnostics::IceBugReportInternalFeatureOutdated {
+                version,
+                note_update: (),
+                note_outdated: (),
+            });
+        } else {
+            dcx.emit_note(session_diagnostics::IceBugReportOutdated {
+                version,
+                bug_report_url,
+                note_update: (),
+                note_url: (),
+            });
+        }
     } else {
-        dcx.emit_note(session_diagnostics::IceBugReport { bug_report_url });
+        if using_internal_features.load(std::sync::atomic::Ordering::Relaxed) {
+            dcx.emit_note(session_diagnostics::IceBugReportInternalFeature);
+        } else {
+            dcx.emit_note(session_diagnostics::IceBugReport { bug_report_url });
+        }
     }
 
     let version = util::version_str!().unwrap_or("unknown_version");

compiler/rustc_driver_impl/src/session_diagnostics.rs

@@ -46,6 +46,27 @@ pub(crate) struct IceBugReport<'a> {
 #[diag(driver_impl_ice_bug_report_internal_feature)]
 pub(crate) struct IceBugReportInternalFeature;
 
+#[derive(Diagnostic)]
+#[diag(driver_impl_ice_bug_report_outdated)]
+pub(crate) struct IceBugReportOutdated<'a> {
+    pub version: &'a str,
+    pub bug_report_url: &'a str,
+    #[note(driver_impl_update)]
+    pub note_update: (),
+    #[note(driver_impl_url)]
+    pub note_url: (),
+}
+
+#[derive(Diagnostic)]
+#[diag(driver_impl_ice_bug_report_internal_feature_outdated)]
+pub(crate) struct IceBugReportInternalFeatureOutdated<'a> {
+    pub version: &'a str,
+    #[note(driver_impl_outdated)]
+    pub note_outdated: (),
+    #[note(driver_impl_update)]
+    pub note_update: (),
+}
+
 #[derive(Diagnostic)]
 #[diag(driver_impl_ice_version)]
 pub(crate) struct IceVersion<'a> {