Auto merge of #136433 - matthiaskrgr:rollup-co27itw, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #133266 (ci: fix explanation why LLVM download is disabled for windows-gnu)
 - #136133 (Fix sentence in process::abort)
 - #136279 (Rename `tcx.ensure()` to `tcx.ensure_ok()`, and improve the associated docs)
 - #136328 (Rework "long type names" printing logic)
 - #136358 (`#[optimize(none)]` implies `#[inline(never)]`)
 - #136368 (Make comma separated lists of anything easier to make for errors)
 - #136412 (Tweak fn pointer suggestion span)

r? `@ghost`
`@rustbot` modify labels: rollup

2 files changed, 32 insertions, 13 deletions

diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 797dcd7b4d1..b96df814852 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -4,6 +4,7 @@ use std::hash::{Hash, Hasher};
 use std::marker::PhantomData;
 use std::ops::{Deref, DerefMut};
 use std::panic;
+use std::path::PathBuf;
 use std::thread::panicking;
 
 use rustc_data_structures::fx::FxIndexMap;
@@ -301,6 +302,7 @@ pub struct DiagInner {
 
     pub is_lint: Option<IsLint>,
 
+    pub long_ty_path: Option<PathBuf>,
     /// With `-Ztrack_diagnostics` enabled,
     /// we print where in rustc this error was emitted.
     pub(crate) emitted_at: DiagLocation,
@@ -324,6 +326,7 @@ impl DiagInner {
             args: Default::default(),
             sort_span: DUMMY_SP,
             is_lint: None,
+            long_ty_path: None,
             emitted_at: DiagLocation::caller(),
         }
     }
@@ -1293,9 +1296,37 @@ impl<'a, G: EmissionGuarantee> Diag<'a, G> {
     /// `cancel`, etc. Afterwards, `drop` is the only code that will be run on
     /// `self`.
     fn take_diag(&mut self) -> DiagInner {
+        if let Some(path) = &self.long_ty_path {
+            self.note(format!(
+                "the full name for the type has been written to '{}'",
+                path.display()
+            ));
+            self.note("consider using `--verbose` to print the full type name to the console");
+        }
         Box::into_inner(self.diag.take().unwrap())
     }
 
+    /// This method allows us to access the path of the file where "long types" are written to.
+    ///
+    /// When calling `Diag::emit`, as part of that we will check if a `long_ty_path` has been set,
+    /// and if it has been then we add a note mentioning the file where the "long types" were
+    /// written to.
+    ///
+    /// When calling `tcx.short_string()` after a `Diag` is constructed, the preferred way of doing
+    /// so is `tcx.short_string(ty, diag.long_ty_path())`. The diagnostic itself is the one that
+    /// keeps the existence of a "long type" anywhere in the diagnostic, so the note telling the
+    /// user where we wrote the file to is only printed once at most, *and* it makes it much harder
+    /// to forget to set it.
+    ///
+    /// If the diagnostic hasn't been created before a "short ty string" is created, then you should
+    /// ensure that this method is called to set it `*diag.long_ty_path() = path`.
+    ///
+    /// As a rule of thumb, if you see or add at least one `tcx.short_string()` call anywhere, in a
+    /// scope, `diag.long_ty_path()` should be called once somewhere close by.
+    pub fn long_ty_path(&mut self) -> &mut Option<PathBuf> {
+        &mut self.long_ty_path
+    }
+
     /// Most `emit_producing_guarantee` functions use this as a starting point.
     fn emit_producing_nothing(mut self) {
         let diag = self.take_diag();
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 549729548f5..a6458c9ffdc 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -65,7 +65,7 @@ pub use rustc_error_messages::{
     SubdiagMessage, fallback_fluent_bundle, fluent_bundle,
 };
 use rustc_lint_defs::LintExpectationId;
-pub use rustc_lint_defs::{Applicability, pluralize};
+pub use rustc_lint_defs::{Applicability, listify, pluralize};
 use rustc_macros::{Decodable, Encodable};
 pub use rustc_span::ErrorGuaranteed;
 pub use rustc_span::fatal_error::{FatalError, FatalErrorMarker};
@@ -1999,18 +1999,6 @@ pub fn a_or_an(s: &str) -> &'static str {
     }
 }
 
-/// Grammatical tool for displaying messages to end users in a nice form.
-///
-/// Take a list ["a", "b", "c"] and output a display friendly version "a, b and c"
-pub fn display_list_with_comma_and<T: std::fmt::Display>(v: &[T]) -> String {
-    match v {
-        [] => "".to_string(),
-        [a] => a.to_string(),
-        [a, b] => format!("{a} and {b}"),
-        [a, v @ ..] => format!("{a}, {}", display_list_with_comma_and(v)),
-    }
-}
-
 #[derive(Clone, Copy, PartialEq, Hash, Debug)]
 pub enum TerminalUrl {
     No,