On overflow errors, do not print out long types

compiler/rustc_middle/src/ty/error.rs

@@ -12,7 +12,12 @@ use rustc_span::{BytePos, Span};
 use rustc_target::spec::abi;
 
 use std::borrow::Cow;
+use std::collections::hash_map::DefaultHasher;
 use std::fmt;
+use std::hash::{Hash, Hasher};
+use std::path::PathBuf;
+
+use super::print::PrettyPrinter;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable, Lift)]
 pub struct ExpectedFound<T> {
@@ -985,6 +990,38 @@ fn foo(&self) -> Self::T { String::new() }
         false
     }
 
+    pub fn short_ty_string(self, ty: Ty<'tcx>) -> Result<String, (String, PathBuf)> {
+        let length_limit = 50;
+        let type_limit = 4;
+        let regular = FmtPrinter::new(self, hir::def::Namespace::TypeNS)
+            .pretty_print_type(ty)
+            .expect("could not write to `String`")
+            .into_buffer();
+        if regular.len() <= length_limit {
+            return Ok(regular);
+        }
+        let short = FmtPrinter::new_with_limit(
+            self,
+            hir::def::Namespace::TypeNS,
+            rustc_session::Limit(type_limit),
+        )
+        .pretty_print_type(ty)
+        .expect("could not write to `String`")
+        .into_buffer();
+        if regular == short {
+            return Ok(regular);
+        }
+        // Multiple types might be shortened in a single error, ensure we create a file for each.
+        let mut s = DefaultHasher::new();
+        ty.hash(&mut s);
+        let hash = s.finish();
+        let path = self.output_filenames(()).temp_path_ext(&format!("long-type-{hash}.txt"), None);
+        match std::fs::write(&path, &regular) {
+            Ok(_) => Err((short, path)),
+            Err(_) => Ok(regular),
+        }
+    }
+
     fn format_generic_args(self, args: &[ty::GenericArg<'tcx>]) -> String {
         FmtPrinter::new(self, hir::def::Namespace::TypeNS)
             .path_generic_args(Ok, args)

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -2733,9 +2733,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     self.resolve_vars_if_possible(data.derived.parent_trait_pred);
                 parent_trait_pred.remap_constness_diag(param_env);
                 let parent_def_id = parent_trait_pred.def_id();
+                let (self_ty, file) =
+                    match self.tcx.short_ty_string(parent_trait_pred.skip_binder().self_ty()) {
+                        Ok(self_ty) => (self_ty, None),
+                        Err((self_ty, file)) => (self_ty, Some(file)),
+                    };
                 let msg = format!(
-                    "required for `{}` to implement `{}`",
+                    "required for `{self_ty}` to implement `{}`",
-                    parent_trait_pred.skip_binder().self_ty(),
                     parent_trait_pred.print_modifiers_and_trait_path()
                 );
                 let mut is_auto_trait = false;
@@ -2764,6 +2768,12 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     _ => err.note(&msg),
                 };
 
+                if let Some(file) = file {
+                    err.note(&format!(
+                        "the full type name has been written to '{}'",
+                        file.display(),
+                    ));
+                }
                 let mut parent_predicate = parent_trait_pred;
                 let mut data = &data.derived;
                 let mut count = 0;
@@ -2804,11 +2814,21 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         count,
                         pluralize!(count)
                     ));
+                    let (self_ty, file) =
+                        match self.tcx.short_ty_string(parent_trait_pred.skip_binder().self_ty()) {
+                            Ok(self_ty) => (self_ty, None),
+                            Err((self_ty, file)) => (self_ty, Some(file)),
+                        };
                     err.note(&format!(
-                        "required for `{}` to implement `{}`",
+                        "required for `{self_ty}` to implement `{}`",
-                        parent_trait_pred.skip_binder().self_ty(),
                         parent_trait_pred.print_modifiers_and_trait_path()
                     ));
+                    if let Some(file) = file {
+                        err.note(&format!(
+                            "the full type name has been written to '{}'",
+                            file.display(),
+                        ));
+                    }
                 }
                 // #74711: avoid a stack overflow
                 ensure_sufficient_stack(|| {

src/test/ui/error-codes/E0275.rs

@@ -1,3 +1,4 @@
+// normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 trait Foo {}
 
 struct Bar<T>(T);

src/test/ui/error-codes/E0275.stderr

@@ -1,15 +1,16 @@
 error[E0275]: overflow evaluating the requirement `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Foo`
-  --> $DIR/E0275.rs:5:33
+  --> $DIR/E0275.rs:6:33
    |
 LL | impl<T> Foo for T where Bar<T>: Foo {}
    |                                 ^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`E0275`)
-note: required for `Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<Bar<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Foo`
+note: required for `Bar<Bar<Bar<Bar<Bar<Bar<...>>>>>>` to implement `Foo`
-  --> $DIR/E0275.rs:5:9
+  --> $DIR/E0275.rs:6:9
    |
 LL | impl<T> Foo for T where Bar<T>: Foo {}
    |         ^^^     ^
+   = note: the full type name has been written to '$TEST_BUILD_DIR/error-codes/E0275/E0275.long-type-hash.txt'
    = note: 127 redundant requirements hidden
    = note: required for `Bar<T>` to implement `Foo`
 

src/test/ui/issues/issue-20413.rs

@@ -1,3 +1,4 @@
+// normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 trait Foo {
     fn answer(self);
 }

src/test/ui/issues/issue-20413.stderr

@@ -1,5 +1,5 @@
 error[E0392]: parameter `T` is never used
-  --> $DIR/issue-20413.rs:5:15
+  --> $DIR/issue-20413.rs:6:15
    |
 LL | struct NoData<T>;
    |               ^ unused parameter
@@ -8,57 +8,62 @@ LL | struct NoData<T>;
    = help: if you intended `T` to be a const parameter, use `const T: usize` instead
 
 error[E0275]: overflow evaluating the requirement `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Foo`
-  --> $DIR/issue-20413.rs:8:36
+  --> $DIR/issue-20413.rs:9:36
    |
 LL | impl<T> Foo for T where NoData<T>: Foo {
    |                                    ^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_20413`)
-note: required for `NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<NoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Foo`
+note: required for `NoData<NoData<NoData<NoData<NoData<NoData<...>>>>>>` to implement `Foo`
-  --> $DIR/issue-20413.rs:8:9
+  --> $DIR/issue-20413.rs:9:9
    |
 LL | impl<T> Foo for T where NoData<T>: Foo {
    |         ^^^     ^
+   = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
    = note: 127 redundant requirements hidden
    = note: required for `NoData<T>` to implement `Foo`
 
 error[E0275]: overflow evaluating the requirement `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Baz`
-  --> $DIR/issue-20413.rs:27:42
+  --> $DIR/issue-20413.rs:28:42
    |
 LL | impl<T> Bar for T where EvenLessData<T>: Baz {
    |                                          ^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_20413`)
-note: required for `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Bar`
+note: required for `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<...>>>>>>` to implement `Bar`
-  --> $DIR/issue-20413.rs:27:9
+  --> $DIR/issue-20413.rs:28:9
    |
 LL | impl<T> Bar for T where EvenLessData<T>: Baz {
    |         ^^^     ^
-note: required for `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Baz`
+   = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
-  --> $DIR/issue-20413.rs:34:9
+note: required for `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<...>>>>>>` to implement `Baz`
+  --> $DIR/issue-20413.rs:35:9
    |
 LL | impl<T> Baz for T where AlmostNoData<T>: Bar {
    |         ^^^     ^
+   = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
    = note: 126 redundant requirements hidden
    = note: required for `EvenLessData<T>` to implement `Baz`
 
 error[E0275]: overflow evaluating the requirement `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>: Bar`
-  --> $DIR/issue-20413.rs:34:42
+  --> $DIR/issue-20413.rs:35:42
    |
 LL | impl<T> Baz for T where AlmostNoData<T>: Bar {
    |                                          ^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_20413`)
-note: required for `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Baz`
+note: required for `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<...>>>>>>` to implement `Baz`
-  --> $DIR/issue-20413.rs:34:9
+  --> $DIR/issue-20413.rs:35:9
    |
 LL | impl<T> Baz for T where AlmostNoData<T>: Bar {
    |         ^^^     ^
-note: required for `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<T>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>` to implement `Bar`
+   = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
-  --> $DIR/issue-20413.rs:27:9
+note: required for `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<...>>>>>>` to implement `Bar`
+  --> $DIR/issue-20413.rs:28:9
    |
 LL | impl<T> Bar for T where EvenLessData<T>: Baz {
    |         ^^^     ^
+   = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
    = note: 126 redundant requirements hidden
    = note: required for `AlmostNoData<T>` to implement `Bar`
 

src/test/ui/recursion/issue-83150.rs

@@ -1,6 +1,7 @@
 // build-fail
 // compile-flags: -Copt-level=0
-//~^^ ERROR overflow evaluating the requirement
+// normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
+//~^^^ ERROR overflow evaluating the requirement
 
 fn main() {
     let mut iter = 0u8..1;

src/test/ui/recursion/issue-83150.stderr

@@ -1,5 +1,5 @@
 warning: function cannot return without recursing
-  --> $DIR/issue-83150.rs:10:1
+  --> $DIR/issue-83150.rs:11:1
    |
 LL | fn func<T: Iterator<Item = u8>>(iter: &mut T) {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@@ -12,9 +12,10 @@ LL |     func(&mut iter.map(|x| x + 1))
 error[E0275]: overflow evaluating the requirement `<std::ops::Range<u8> as Iterator>::Item`
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_83150`)
-   = note: required for `Map<&mut std::ops::Range<u8>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>` to implement `Iterator`
+   = note: required for `Map<&mut std::ops::Range<u8>, [closure@$DIR/issue-83150.rs:12:24: 12:27]>` to implement `Iterator`
    = note: 64 redundant requirements hidden
-   = note: required for `&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut Map<&mut std::ops::Range<u8>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>, [closure@$DIR/issue-83150.rs:11:24: 11:27]>` to implement `Iterator`
+   = note: required for `&mut Map<&mut Map<&mut Map<_, _>, _>, _>` to implement `Iterator`
+   = note: the full type name has been written to '$TEST_BUILD_DIR/recursion/issue-83150/issue-83150.long-type-hash.txt'
 
 error: aborting due to previous error; 1 warning emitted
 

src/test/ui/traits/issue-91949-hangs-on-recursion.rs

@@ -2,6 +2,7 @@
 // compile-flags: -Zinline-mir=no
 // error-pattern: overflow evaluating the requirement `(): Sized`
 // error-pattern: function cannot return without recursing
+// normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 
 // Regression test for #91949.
 // This hanged *forever* on 1.56, fixed by #90423.