Auto merge of #116849 - oli-obk:error_shenanigans, r=cjgillot

Avoid a `track_errors` by bubbling up most errors from `check_well_formed`

I believe `track_errors` is mostly papering over issues that a sufficiently convoluted query graph can hit. I made this change, while the actual change I want to do is to stop bailing out early on errors, and instead use this new `ErrorGuaranteed` to invoke `check_well_formed` for individual items before doing all the `typeck` logic on them.

This works towards resolving https://github.com/rust-lang/rust/issues/97477 and various other ICEs, as well as allowing us to use parallel rustc more (which is currently rather limited/bottlenecked due to the very sequential nature in which we do `rustc_hir_analysis::check_crate`)

cc `@SparrowLii` `@Zoxc` for the new `try_par_for_each_in` function

compiler/rustc_middle/src/hir/map/mod.rs

@@ -6,7 +6,7 @@ use rustc_ast as ast;
 use rustc_data_structures::fingerprint::Fingerprint;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::svh::Svh;
-use rustc_data_structures::sync::{par_for_each_in, DynSend, DynSync};
+use rustc_data_structures::sync::{par_for_each_in, try_par_for_each_in, DynSend, DynSync};
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId, LOCAL_CRATE};
 use rustc_hir::definitions::{DefKey, DefPath, DefPathData, DefPathHash};
@@ -16,7 +16,7 @@ use rustc_index::Idx;
 use rustc_middle::hir::nested_filter;
 use rustc_span::def_id::StableCrateId;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
-use rustc_span::Span;
+use rustc_span::{ErrorGuaranteed, Span};
 use rustc_target::spec::abi::Abi;
 
 #[inline]
@@ -632,6 +632,17 @@ impl<'hir> Map<'hir> {
         })
     }
 
+    #[inline]
+    pub fn try_par_for_each_module(
+        self,
+        f: impl Fn(LocalModDefId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
+    ) -> Result<(), ErrorGuaranteed> {
+        let crate_items = self.tcx.hir_crate_items(());
+        try_par_for_each_in(&crate_items.submodules[..], |module| {
+            f(LocalModDefId::new_unchecked(module.def_id))
+        })
+    }
+
     /// Returns an iterator for the nodes in the ancestor tree of the `current_id`
     /// until the crate root is reached. Prefer this over your own loop using `parent_id`.
     #[inline]

compiler/rustc_middle/src/hir/mod.rs

@@ -9,12 +9,12 @@ pub mod place;
 use crate::query::Providers;
 use crate::ty::{EarlyBinder, ImplSubject, TyCtxt};
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_data_structures::sync::{par_for_each_in, DynSend, DynSync};
+use rustc_data_structures::sync::{try_par_for_each_in, DynSend, DynSync};
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId};
 use rustc_hir::*;
 use rustc_query_system::ich::StableHashingContext;
-use rustc_span::{ExpnId, DUMMY_SP};
+use rustc_span::{ErrorGuaranteed, ExpnId, DUMMY_SP};
 
 /// Top-level HIR node for current owner. This only contains the node for which
 /// `HirId::local_id == 0`, and excludes bodies.
@@ -78,20 +78,32 @@ impl ModuleItems {
         self.owners().map(|id| id.def_id)
     }
 
-    pub fn par_items(&self, f: impl Fn(ItemId) + DynSend + DynSync) {
-        par_for_each_in(&self.items[..], |&id| f(id))
+    pub fn par_items(
+        &self,
+        f: impl Fn(ItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
+    ) -> Result<(), ErrorGuaranteed> {
+        try_par_for_each_in(&self.items[..], |&id| f(id))
     }
 
-    pub fn par_trait_items(&self, f: impl Fn(TraitItemId) + DynSend + DynSync) {
-        par_for_each_in(&self.trait_items[..], |&id| f(id))
+    pub fn par_trait_items(
+        &self,
+        f: impl Fn(TraitItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
+    ) -> Result<(), ErrorGuaranteed> {
+        try_par_for_each_in(&self.trait_items[..], |&id| f(id))
     }
 
-    pub fn par_impl_items(&self, f: impl Fn(ImplItemId) + DynSend + DynSync) {
-        par_for_each_in(&self.impl_items[..], |&id| f(id))
+    pub fn par_impl_items(
+        &self,
+        f: impl Fn(ImplItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
+    ) -> Result<(), ErrorGuaranteed> {
+        try_par_for_each_in(&self.impl_items[..], |&id| f(id))
     }
 
-    pub fn par_foreign_items(&self, f: impl Fn(ForeignItemId) + DynSend + DynSync) {
-        par_for_each_in(&self.foreign_items[..], |&id| f(id))
+    pub fn par_foreign_items(
+        &self,
+        f: impl Fn(ForeignItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
+    ) -> Result<(), ErrorGuaranteed> {
+        try_par_for_each_in(&self.foreign_items[..], |&id| f(id))
     }
 }
 

compiler/rustc_middle/src/query/mod.rs

@@ -25,7 +25,9 @@ use crate::mir::interpret::{
 use crate::mir::interpret::{LitToConstError, LitToConstInput};
 use crate::mir::mono::CodegenUnit;
 use crate::query::erase::{erase, restore, Erase};
-use crate::query::plumbing::{query_ensure, query_get_at, CyclePlaceholder, DynamicQuery};
+use crate::query::plumbing::{
+    query_ensure, query_ensure_error_guaranteed, query_get_at, CyclePlaceholder, DynamicQuery,
+};
 use crate::thir;
 use crate::traits::query::{
     CanonicalPredicateGoal, CanonicalProjectionGoal, CanonicalTyGoal,
@@ -965,8 +967,9 @@ rustc_queries! {
         desc { |tcx| "checking that impls are well-formed in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_type_wf(key: LocalModDefId) -> () {
+    query check_mod_type_wf(key: LocalModDefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking that types are well-formed in {}", describe_as_module(key, tcx) }
+        ensure_forwards_result_if_red
     }
 
     query collect_mod_item_types(key: LocalModDefId) -> () {
@@ -1499,8 +1502,9 @@ rustc_queries! {
         feedable
     }
 
-    query check_well_formed(key: hir::OwnerId) -> () {
+    query check_well_formed(key: hir::OwnerId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking that `{}` is well-formed", tcx.def_path_str(key) }
+        ensure_forwards_result_if_red
     }
 
     // The `DefId`s of all non-generic functions and statics in the given crate

compiler/rustc_middle/src/query/plumbing.rs

@@ -173,6 +173,45 @@ pub fn query_ensure<'tcx, Cache>(
     }
 }
 
+#[inline]
+pub fn query_ensure_error_guaranteed<'tcx, Cache>(
+    tcx: TyCtxt<'tcx>,
+    execute_query: fn(TyCtxt<'tcx>, Span, Cache::Key, QueryMode) -> Option<Cache::Value>,
+    query_cache: &Cache,
+    key: Cache::Key,
+    check_cache: bool,
+) -> Result<(), ErrorGuaranteed>
+where
+    Cache: QueryCache<Value = super::erase::Erase<Result<(), ErrorGuaranteed>>>,
+{
+    let key = key.into_query_param();
+    if let Some(res) = try_get_cached(tcx, query_cache, &key) {
+        super::erase::restore(res)
+    } else {
+        execute_query(tcx, DUMMY_SP, key, QueryMode::Ensure { check_cache })
+            .map(super::erase::restore)
+            // Either we actually executed the query, which means we got a full `Result`,
+            // or we can just assume the query succeeded, because it was green in the
+            // incremental cache. If it is green, that means that the previous compilation
+            // that wrote to the incremental cache compiles successfully. That is only
+            // possible if the cache entry was `Ok(())`, so we emit that here, without
+            // actually encoding the `Result` in the cache or loading it from there.
+            .unwrap_or(Ok(()))
+    }
+}
+
+macro_rules! query_ensure {
+    ([]$($args:tt)*) => {
+        query_ensure($($args)*)
+    };
+    ([(ensure_forwards_result_if_red) $($rest:tt)*]$($args:tt)*) => {
+        query_ensure_error_guaranteed($($args)*)
+    };
+    ([$other:tt $($modifiers:tt)*]$($args:tt)*) => {
+        query_ensure!([$($modifiers)*]$($args)*)
+    };
+}
+
 macro_rules! query_helper_param_ty {
     (DefId) => { impl IntoQueryParam<DefId> };
     (LocalDefId) => { impl IntoQueryParam<LocalDefId> };
@@ -220,6 +259,18 @@ macro_rules! separate_provide_extern_decl {
     };
 }
 
+macro_rules! ensure_result {
+    ([][$ty:ty]) => {
+        ()
+    };
+    ([(ensure_forwards_result_if_red) $($rest:tt)*][$ty:ty]) => {
+        Result<(), ErrorGuaranteed>
+    };
+    ([$other:tt $($modifiers:tt)*][$($args:tt)*]) => {
+        ensure_result!([$($modifiers)*][$($args)*])
+    };
+}
+
 macro_rules! separate_provide_extern_default {
     ([][$name:ident]) => {
         ()
@@ -343,14 +394,15 @@ macro_rules! define_callbacks {
         impl<'tcx> TyCtxtEnsure<'tcx> {
             $($(#[$attr])*
             #[inline(always)]
-            pub fn $name(self, key: query_helper_param_ty!($($K)*)) {
-                query_ensure(
+            pub fn $name(self, key: query_helper_param_ty!($($K)*)) -> ensure_result!([$($modifiers)*][$V]) {
+                query_ensure!(
+                    [$($modifiers)*]
                     self.tcx,
                     self.tcx.query_system.fns.engine.$name,
                     &self.tcx.query_system.caches.$name,
                     key.into_query_param(),
                     false,
-                );
+                )
             })*
         }