Stop telling people to submit bugs for internal feature ICEs

This keeps track of usage of internal features, and changes the message
to instead tell them that using internal features is not supported.

See MCP 620.

compiler/rustc_driver_impl/messages.ftl

@@ -1,5 +1,6 @@
 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_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

@@ -60,7 +60,7 @@ use std::path::PathBuf;
 use std::process::{self, Command, Stdio};
 use std::str;
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::OnceLock;
+use std::sync::{Arc, OnceLock};
 use std::time::{Instant, SystemTime};
 use time::format_description::well_known::Rfc3339;
 use time::OffsetDateTime;
@@ -224,11 +224,18 @@ pub struct RunCompiler<'a, 'b> {
     file_loader: Option<Box<dyn FileLoader + Send + Sync>>,
     make_codegen_backend:
         Option<Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>>,
+    using_internal_features: Arc<std::sync::atomic::AtomicBool>,
 }
 
 impl<'a, 'b> RunCompiler<'a, 'b> {
     pub fn new(at_args: &'a [String], callbacks: &'b mut (dyn Callbacks + Send)) -> Self {
-        Self { at_args, callbacks, file_loader: None, make_codegen_backend: None }
+        Self {
+            at_args,
+            callbacks,
+            file_loader: None,
+            make_codegen_backend: None,
+            using_internal_features: Arc::default(),
+        }
     }
 
     /// Set a custom codegen backend.
@@ -260,9 +267,23 @@ impl<'a, 'b> RunCompiler<'a, 'b> {
         self
     }
 
+    /// Set the session-global flag that checks whether internal features have been used,
+    /// suppressing the message about submitting an issue in ICEs when enabled.
+    #[must_use]
+    pub fn set_using_internal_features(mut self, using_internal_features: Arc<AtomicBool>) -> Self {
+        self.using_internal_features = using_internal_features;
+        self
+    }
+
     /// Parse args and run the compiler.
     pub fn run(self) -> interface::Result<()> {
-        run_compiler(self.at_args, self.callbacks, self.file_loader, self.make_codegen_backend)
+        run_compiler(
+            self.at_args,
+            self.callbacks,
+            self.file_loader,
+            self.make_codegen_backend,
+            self.using_internal_features,
+        )
     }
 }
 
@@ -273,6 +294,7 @@ fn run_compiler(
     make_codegen_backend: Option<
         Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>,
     >,
+    using_internal_features: Arc<std::sync::atomic::AtomicBool>,
 ) -> interface::Result<()> {
     let mut early_error_handler = EarlyErrorHandler::new(ErrorOutputType::default());
 
@@ -316,6 +338,7 @@ fn run_compiler(
         override_queries: None,
         make_codegen_backend,
         registry: diagnostics_registry(),
+        using_internal_features,
         expanded_args: args,
     };
 
@@ -1323,8 +1346,12 @@ fn ice_path() -> &'static Option<PathBuf> {
 /// If you have no extra info to report, pass the empty closure `|_| ()` as the argument to
 /// extra_info.
 ///
+/// Returns a flag that can be set to disable the note for submitting a bug. This can be passed to
+/// [`RunCompiler::set_using_internal_features`] to let macro expansion set it when encountering
+/// internal features.
+///
 /// A custom rustc driver can skip calling this to set up a custom ICE hook.
-pub fn install_ice_hook(bug_report_url: &'static str, extra_info: fn(&Handler)) {
+pub fn install_ice_hook(bug_report_url: &'static str, extra_info: fn(&Handler)) -> Arc<AtomicBool> {
     // If the user has not explicitly overridden "RUST_BACKTRACE", then produce
     // full backtraces. When a compiler ICE happens, we want to gather
     // as much information as possible to present in the issue opened
@@ -1335,6 +1362,8 @@ pub fn install_ice_hook(bug_report_url: &'static str, extra_info: fn(&Handler))
         std::env::set_var("RUST_BACKTRACE", "full");
     }
 
+    let using_internal_features = Arc::new(std::sync::atomic::AtomicBool::default());
+    let using_internal_features_hook = using_internal_features.clone();
     panic::update_hook(Box::new(
         move |default_hook: &(dyn Fn(&PanicInfo<'_>) + Send + Sync + 'static),
               info: &PanicInfo<'_>| {
@@ -1384,9 +1413,11 @@ pub fn install_ice_hook(bug_report_url: &'static str, extra_info: fn(&Handler))
             }
 
             // Print the ICE message
-            report_ice(info, bug_report_url, extra_info);
+            report_ice(info, bug_report_url, extra_info, &using_internal_features_hook);
         },
     ));
+
+    using_internal_features
 }
 
 /// Prints the ICE message, including query stack, but without backtrace.
@@ -1395,7 +1426,12 @@ pub fn install_ice_hook(bug_report_url: &'static str, extra_info: fn(&Handler))
 ///
 /// When `install_ice_hook` is called, this function will be called as the panic
 /// hook.
-fn report_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str, extra_info: fn(&Handler)) {
+fn report_ice(
+    info: &panic::PanicInfo<'_>,
+    bug_report_url: &str,
+    extra_info: fn(&Handler),
+    using_internal_features: &AtomicBool,
+) {
     let fallback_bundle =
         rustc_errors::fallback_fluent_bundle(crate::DEFAULT_LOCALE_RESOURCES.to_vec(), false);
     let emitter = Box::new(rustc_errors::emitter::EmitterWriter::stderr(
@@ -1412,7 +1448,11 @@ fn report_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str, extra_info: fn(
         handler.emit_err(session_diagnostics::Ice);
     }
 
-    handler.emit_note(session_diagnostics::IceBugReport { bug_report_url });
+    if using_internal_features.load(std::sync::atomic::Ordering::Relaxed) {
+        handler.emit_note(session_diagnostics::IceBugReportInternalFeature);
+    } else {
+        handler.emit_note(session_diagnostics::IceBugReport { bug_report_url });
+    }
 
     let version = util::version_str!().unwrap_or("unknown_version");
     let triple = config::host_triple();
@@ -1496,7 +1536,7 @@ pub fn main() -> ! {
     init_rustc_env_logger(&handler);
     signal_handler::install();
     let mut callbacks = TimePassesCallbacks::default();
-    install_ice_hook(DEFAULT_BUG_REPORT_URL, |_| ());
+    let using_internal_features = install_ice_hook(DEFAULT_BUG_REPORT_URL, |_| ());
     let exit_code = catch_with_exit_code(|| {
         let args = env::args_os()
             .enumerate()
@@ -1506,7 +1546,9 @@ pub fn main() -> ! {
                 })
             })
             .collect::<Vec<_>>();
-        RunCompiler::new(&args, &mut callbacks).run()
+        RunCompiler::new(&args, &mut callbacks)
+            .set_using_internal_features(using_internal_features)
+            .run()
     });
 
     if let Some(format) = callbacks.time_passes {

compiler/rustc_driver_impl/src/session_diagnostics.rs

@@ -42,6 +42,10 @@ pub(crate) struct IceBugReport<'a> {
     pub bug_report_url: &'a str,
 }
 
+#[derive(Diagnostic)]
+#[diag(driver_impl_ice_bug_report_internal_feature)]
+pub(crate) struct IceBugReportInternalFeature;
+
 #[derive(Diagnostic)]
 #[diag(driver_impl_ice_version)]
 pub(crate) struct IceVersion<'a> {

compiler/rustc_expand/src/config.rs

@@ -35,7 +35,7 @@ pub struct StripUnconfigured<'a> {
     pub lint_node_id: NodeId,
 }
 
-pub fn features(sess: &Session, krate_attrs: &[Attribute]) -> Features {
+pub fn features(sess: &Session, krate_attrs: &[Attribute], crate_name: Symbol) -> Features {
     fn feature_list(attr: &Attribute) -> ThinVec<ast::NestedMetaItem> {
         if attr.has_name(sym::feature)
             && let Some(list) = attr.meta_item_list()
@@ -167,6 +167,15 @@ pub fn features(sess: &Session, krate_attrs: &[Attribute]) -> Features {
             // If the declared feature is unstable, record it.
             if let Some(f) = UNSTABLE_FEATURES.iter().find(|f| name == f.feature.name) {
                 (f.set_enabled)(&mut features);
+                // When the ICE comes from core, alloc or std (approximation of the standard library), there's a chance
+                // that the person hitting the ICE may be using -Zbuild-std or similar with an untested target.
+                // The bug is probably in the standard library and not the compiler in that case, but that doesn't
+                // really matter - we want a bug report.
+                if features.internal(name)
+                    && ![sym::core, sym::alloc, sym::std].contains(&crate_name)
+                {
+                    sess.using_internal_features.store(true, std::sync::atomic::Ordering::Relaxed);
+                }
                 features.set_declared_lang_feature(name, mi.span(), None);
                 continue;
             }

compiler/rustc_interface/src/interface.rs

@@ -23,6 +23,7 @@ use rustc_span::source_map::{FileLoader, FileName};
 use rustc_span::symbol::sym;
 use std::path::PathBuf;
 use std::result;
+use std::sync::Arc;
 
 pub type Result<T> = result::Result<T, ErrorGuaranteed>;
 
@@ -280,6 +281,12 @@ pub struct Config {
     /// Registry of diagnostics codes.
     pub registry: Registry,
 
+    /// The inner atomic value is set to true when a feature marked as `internal` is
+    /// enabled. Makes it so that "please report a bug" is hidden, as ICEs with
+    /// internal features are wontfix, and they are usually the cause of the ICEs.
+    /// None signifies that this is not tracked.
+    pub using_internal_features: Arc<std::sync::atomic::AtomicBool>,
+
     /// All commandline args used to invoke the compiler, with @file args fully expanded.
     /// This will only be used within debug info, e.g. in the pdb file on windows
     /// This is mainly useful for other tools that reads that debuginfo to figure out
@@ -323,6 +330,7 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
                 config.make_codegen_backend,
                 registry.clone(),
                 config.ice_file,
+                config.using_internal_features,
                 config.expanded_args,
             );
 

compiler/rustc_interface/src/queries.rs

@@ -181,9 +181,11 @@ impl<'tcx> Queries<'tcx> {
                 feed.crate_name(crate_name);
 
                 let feed = tcx.feed_unit_query();
-                feed.features_query(
-                    tcx.arena.alloc(rustc_expand::config::features(sess, &pre_configured_attrs)),
-                );
+                feed.features_query(tcx.arena.alloc(rustc_expand::config::features(
+                    sess,
+                    &pre_configured_attrs,
+                    crate_name,
+                )));
                 feed.crate_for_resolver(tcx.arena.alloc(Steal::new((krate, pre_configured_attrs))));
             });
             Ok(qcx)

compiler/rustc_interface/src/tests.rs

@@ -35,6 +35,7 @@ use rustc_target::spec::{RelroLevel, SanitizerSet, SplitDebuginfo, StackProtecto
 use std::collections::{BTreeMap, BTreeSet};
 use std::num::NonZeroUsize;
 use std::path::{Path, PathBuf};
+use std::sync::Arc;
 
 type CfgSpecs = FxHashSet<(String, Option<String>)>;
 
@@ -69,6 +70,7 @@ fn mk_session(handler: &mut EarlyErrorHandler, matches: getopts::Matches) -> (Se
         None,
         "",
         None,
+        Arc::default(),
         Default::default(),
     );
     (sess, cfg)

compiler/rustc_interface/src/util.rs

@@ -26,7 +26,7 @@ use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
 use std::mem;
 use std::path::{Path, PathBuf};
 use std::sync::atomic::{AtomicBool, Ordering};
-use std::sync::OnceLock;
+use std::sync::{Arc, OnceLock};
 use std::thread;
 
 /// Function pointer type that constructs a new CodegenBackend.
@@ -71,6 +71,7 @@ pub fn create_session(
     >,
     descriptions: Registry,
     ice_file: Option<PathBuf>,
+    using_internal_features: Arc<AtomicBool>,
     expanded_args: Vec<String>,
 ) -> (Session, Box<dyn CodegenBackend>) {
     let codegen_backend = if let Some(make_codegen_backend) = make_codegen_backend {
@@ -114,6 +115,7 @@ pub fn create_session(
         target_override,
         rustc_version_str().unwrap_or("unknown"),
         ice_file,
+        using_internal_features,
         expanded_args,
     );
 

compiler/rustc_session/src/session.rs

@@ -44,7 +44,7 @@ use std::fmt;
 use std::ops::{Div, Mul};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
-use std::sync::Arc;
+use std::sync::{atomic::AtomicBool, Arc};
 use std::time::Duration;
 
 pub struct OptimizationFuel {
@@ -201,6 +201,12 @@ pub struct Session {
     /// The version of the rustc process, possibly including a commit hash and description.
     pub cfg_version: &'static str,
 
+    /// The inner atomic value is set to true when a feature marked as `internal` is
+    /// enabled. Makes it so that "please report a bug" is hidden, as ICEs with
+    /// internal features are wontfix, and they are usually the cause of the ICEs.
+    /// None signifies that this is not tracked.
+    pub using_internal_features: Arc<AtomicBool>,
+
     /// All commandline args used to invoke the compiler, with @file args fully expanded.
     /// This will only be used within debug info, e.g. in the pdb file on windows
     /// This is mainly useful for other tools that reads that debuginfo to figure out
@@ -1333,6 +1339,7 @@ pub fn build_session(
     target_override: Option<Target>,
     cfg_version: &'static str,
     ice_file: Option<PathBuf>,
+    using_internal_features: Arc<AtomicBool>,
     expanded_args: Vec<String>,
 ) -> Session {
     // FIXME: This is not general enough to make the warning lint completely override
@@ -1469,6 +1476,7 @@ pub fn build_session(
         target_features: Default::default(),
         unstable_target_features: Default::default(),
         cfg_version,
+        using_internal_features,
         expanded_args,
     };
 

src/librustdoc/core.rs

@@ -23,6 +23,7 @@ use std::cell::RefCell;
 use std::mem;
 use std::rc::Rc;
 use std::sync::LazyLock;
+use std::sync::{atomic::AtomicBool, Arc};
 
 use crate::clean::inline::build_external_trait;
 use crate::clean::{self, ItemId};
@@ -198,6 +199,7 @@ pub(crate) fn create_config(
         ..
     }: RustdocOptions,
     RenderOptions { document_private, .. }: &RenderOptions,
+    using_internal_features: Arc<AtomicBool>,
 ) -> rustc_interface::Config {
     // Add the doc cfg into the doc build.
     cfgs.push("doc".to_string());
@@ -292,6 +294,7 @@ pub(crate) fn create_config(
         make_codegen_backend: None,
         registry: rustc_driver::diagnostics_registry(),
         ice_file: None,
+        using_internal_features,
         expanded_args,
     }
 }

src/librustdoc/doctest.rs

@@ -109,6 +109,7 @@ pub(crate) fn run(options: RustdocOptions) -> Result<(), ErrorGuaranteed> {
         make_codegen_backend: None,
         registry: rustc_driver::diagnostics_registry(),
         ice_file: None,
+        using_internal_features: Arc::default(),
         expanded_args: options.expanded_args.clone(),
     };