Move the QueryOverflow and QueryOverflowNote errors.

They are defined in `rustc_query_system` but used in `rustc_query_impl`.
This is very much *not* how things are supposed to be done; I suspect
someone got lazy and took a shortcut at some point.

This commit moves the errors into `rustc_query_impl`. This requires more
lines of code to give `rustc_query_impl` an errors module, but it's
worthwhile to do things in the normal way instead of a weird exceptional
way.

Author: nnethercote

Cargo.lock

@@ -4534,9 +4534,11 @@ version = "0.0.0"
 dependencies = [
  "measureme",
  "rustc_data_structures",
+ "rustc_errors",
  "rustc_hashes",
  "rustc_hir",
  "rustc_index",
+ "rustc_macros",
  "rustc_middle",
  "rustc_query_system",
  "rustc_serialize",

compiler/rustc_query_impl/Cargo.toml

@@ -7,9 +7,11 @@ edition = "2024"
 # tidy-alphabetical-start
 measureme = "12.0.1"
 rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_errors = { path = "../rustc_errors" }
 rustc_hashes = { path = "../rustc_hashes" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
+rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_query_system = { path = "../rustc_query_system" }
 rustc_serialize = { path = "../rustc_serialize" }

compiler/rustc_query_impl/src/error.rs

@@ -0,0 +1,24 @@
+use rustc_hir::limit::Limit;
+use rustc_macros::{Diagnostic, Subdiagnostic};
+use rustc_span::{Span, Symbol};
+
+#[derive(Diagnostic)]
+#[help(
+    "consider increasing the recursion limit by adding a `#![recursion_limit = \"{$suggested_limit}\"]` attribute to your crate (`{$crate_name}`)"
+)]
+#[diag("queries overflow the depth limit!")]
+pub(crate) struct QueryOverflow {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub note: QueryOverflowNote,
+    pub suggested_limit: Limit,
+    pub crate_name: Symbol,
+}
+
+#[derive(Subdiagnostic)]
+#[note("query depth increased by {$depth} when {$desc}")]
+pub(crate) struct QueryOverflowNote {
+    pub desc: String,
+    pub depth: usize,
+}

compiler/rustc_query_impl/src/lib.rs

@@ -39,6 +39,8 @@ pub use crate::plumbing::{QueryCtxt, query_key_hash_verify_all};
 mod profiling_support;
 pub use self::profiling_support::alloc_self_profile_query_strings;
 
+mod error;
+
 #[derive(ConstParamTy)] // Allow this struct to be used for const-generic values.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 struct QueryFlags {

compiler/rustc_query_impl/src/plumbing.rs

@@ -30,11 +30,11 @@ use rustc_query_system::query::{
     QueryCache, QueryContext, QueryDispatcher, QueryJobId, QueryMap, QuerySideEffect,
     QueryStackDeferred, QueryStackFrame, QueryStackFrameExtra, force_query,
 };
-use rustc_query_system::{QueryOverflow, QueryOverflowNote};
 use rustc_serialize::{Decodable, Encodable};
 use rustc_span::def_id::LOCAL_CRATE;
 
 use crate::QueryDispatcherUnerased;
+use crate::error::{QueryOverflow, QueryOverflowNote};
 
 /// Implements [`QueryContext`] for use by [`rustc_query_system`], since that
 /// crate does not have direct access to [`TyCtxt`].

compiler/rustc_query_system/src/error.rs

@@ -1,7 +1,6 @@
 use rustc_errors::codes::*;
-use rustc_hir::limit::Limit;
 use rustc_macros::{Diagnostic, Subdiagnostic};
-use rustc_span::{Span, Symbol};
+use rustc_span::Span;
 
 #[derive(Subdiagnostic)]
 #[note("...which requires {$desc}...")]
@@ -75,24 +74,3 @@ pub(crate) struct IncrementCompilation {
     pub run_cmd: String,
     pub dep_node: String,
 }
-
-#[derive(Diagnostic)]
-#[help(
-    "consider increasing the recursion limit by adding a `#![recursion_limit = \"{$suggested_limit}\"]` attribute to your crate (`{$crate_name}`)"
-)]
-#[diag("queries overflow the depth limit!")]
-pub struct QueryOverflow {
-    #[primary_span]
-    pub span: Span,
-    #[subdiagnostic]
-    pub note: QueryOverflowNote,
-    pub suggested_limit: Limit,
-    pub crate_name: Symbol,
-}
-
-#[derive(Subdiagnostic)]
-#[note("query depth increased by {$depth} when {$desc}")]
-pub struct QueryOverflowNote {
-    pub desc: String,
-    pub depth: usize,
-}

compiler/rustc_query_system/src/lib.rs

@@ -10,5 +10,3 @@ pub mod dep_graph;
 mod error;
 pub mod ich;
 pub mod query;
-
-pub use error::{QueryOverflow, QueryOverflowNote};