diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 09141afd1370..20171f72c410 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -738,6 +738,7 @@ fn test_unstable_options_tracking_hash() {
     untracked!(unstable_options, true);
     untracked!(validate_mir, true);
     untracked!(verbose, true);
+    untracked!(write_long_types_to_disk, true);
     // tidy-alphabetical-end
 
     macro_rules! tracked {
diff --git a/compiler/rustc_middle/src/ty/error.rs b/compiler/rustc_middle/src/ty/error.rs
index c794c3faded1..3fdbaf5e9477 100644
--- a/compiler/rustc_middle/src/ty/error.rs
+++ b/compiler/rustc_middle/src/ty/error.rs
@@ -339,12 +339,17 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn short_ty_string(self, ty: Ty<'tcx>) -> (String, Option<PathBuf>) {
-        let width = self.sess.diagnostic_width();
-        let length_limit = width.saturating_sub(30);
         let regular = FmtPrinter::new(self, hir::def::Namespace::TypeNS)
             .pretty_print_type(ty)
             .expect("could not write to `String`")
             .into_buffer();
+
+        if !self.sess.opts.unstable_opts.write_long_types_to_disk {
+            return (regular, None);
+        }
+
+        let width = self.sess.diagnostic_width();
+        let length_limit = width.saturating_sub(30);
         if regular.len() <= width {
             return (regular, None);
         }
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 87d67c099ced..a317cc2c1345 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1875,6 +1875,8 @@ written to standard error output)"),
         Requires `-Clto[=[fat,yes]]`"),
     wasi_exec_model: Option<WasiExecModel> = (None, parse_wasi_exec_model, [TRACKED],
         "whether to build a wasi command or reactor"),
+    write_long_types_to_disk: bool = (true, parse_bool, [UNTRACKED],
+        "whether long type names should be written to files instead of being printed in errors"),
     // tidy-alphabetical-end
 
     // If you add a new option, please update:
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index ac19fe078f09..2b4c1183ee7a 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -2330,6 +2330,7 @@ impl<'test> TestCx<'test> {
                 // Hide line numbers to reduce churn
                 rustc.arg("-Zui-testing");
                 rustc.arg("-Zdeduplicate-diagnostics=no");
+                rustc.arg("-Zwrite-long-types-to-disk=no");
                 // FIXME: use this for other modes too, for perf?
                 rustc.arg("-Cstrip=debuginfo");
             }
diff --git a/tests/ui/diagnostic-width/E0271.stderr b/tests/ui/diagnostic-width/E0271.stderr
index 52f415037d35..c1b8b32071ce 100644
--- a/tests/ui/diagnostic-width/E0271.stderr
+++ b/tests/ui/diagnostic-width/E0271.stderr
@@ -15,8 +15,7 @@ note: expected this to be `Foo`
    |
 LL |     type Error = E;
    |                  ^
-   = note: required for the cast from `Box<Result<..., ...>>` to `Box<(dyn Future<Error = Foo> + 'static)>`
-   = note: the full name for the source type has been written to '$TEST_BUILD_DIR/diagnostic-width/E0271/E0271.long-type-hash.txt'
+   = note: required for the cast from `Box<Result<Result<(), Result<Result<(), Result<Result<(), Option<{integer}>>, ()>>, ()>>, ()>>` to `Box<(dyn Future<Error = Foo> + 'static)>`
 
 error: aborting due to previous error
 
diff --git a/tests/ui/diagnostic-width/long-E0308.rs b/tests/ui/diagnostic-width/long-E0308.rs
index f021f1029334..0ae5e19ab2af 100644
--- a/tests/ui/diagnostic-width/long-E0308.rs
+++ b/tests/ui/diagnostic-width/long-E0308.rs
@@ -1,4 +1,4 @@
-// compile-flags: --diagnostic-width=60
+// compile-flags: --diagnostic-width=60 -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 
 mod a {
diff --git a/tests/ui/error-codes/E0271.rs b/tests/ui/error-codes/E0271.rs
index f27190754348..ec6b8b5532e6 100644
--- a/tests/ui/error-codes/E0271.rs
+++ b/tests/ui/error-codes/E0271.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 trait Trait { type AssociatedType; }
 
 fn foo<T>(t: T) where T: Trait<AssociatedType=u32> {
diff --git a/tests/ui/error-codes/E0271.stderr b/tests/ui/error-codes/E0271.stderr
index 1e2f4383459e..98b5aa83da61 100644
--- a/tests/ui/error-codes/E0271.stderr
+++ b/tests/ui/error-codes/E0271.stderr
@@ -1,5 +1,5 @@
 error[E0271]: type mismatch resolving `<i8 as Trait>::AssociatedType == u32`
-  --> $DIR/E0271.rs:10:9
+  --> $DIR/E0271.rs:11:9
    |
 LL |     foo(3_i8);
    |     --- ^^^^ type mismatch resolving `<i8 as Trait>::AssociatedType == u32`
@@ -7,12 +7,12 @@ LL |     foo(3_i8);
    |     required by a bound introduced by this call
    |
 note: expected this to be `u32`
-  --> $DIR/E0271.rs:7:43
+  --> $DIR/E0271.rs:8:43
    |
 LL | impl Trait for i8 { type AssociatedType = &'static str; }
    |                                           ^^^^^^^^^^^^
 note: required by a bound in `foo`
-  --> $DIR/E0271.rs:3:32
+  --> $DIR/E0271.rs:4:32
    |
 LL | fn foo<T>(t: T) where T: Trait<AssociatedType=u32> {
    |                                ^^^^^^^^^^^^^^^^^^ required by this bound in `foo`
diff --git a/tests/ui/error-codes/E0275.rs b/tests/ui/error-codes/E0275.rs
index 95d7f85f1054..5119544e29fe 100644
--- a/tests/ui/error-codes/E0275.rs
+++ b/tests/ui/error-codes/E0275.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 trait Foo {}
 
diff --git a/tests/ui/error-codes/E0275.stderr b/tests/ui/error-codes/E0275.stderr
index 03c37d6f0e1d..1ddb058d0fd1 100644
--- a/tests/ui/error-codes/E0275.stderr
+++ b/tests/ui/error-codes/E0275.stderr
@@ -1,12 +1,12 @@
 error[E0275]: overflow evaluating the requirement `Bar<Bar<Bar<Bar<Bar<Bar<Bar<...>>>>>>>: Foo`
-  --> $DIR/E0275.rs:6:33
+  --> $DIR/E0275.rs:7:33
    |
 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<...>>>>>>>>>>>>>>>>>>>>>` to implement `Foo`
-  --> $DIR/E0275.rs:6:9
+  --> $DIR/E0275.rs:7:9
    |
 LL | impl<T> Foo for T where Bar<T>: Foo {}
    |         ^^^     ^               --- unsatisfied trait bound introduced here
diff --git a/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.rs b/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.rs
index d34b7a29623c..3ee2669a15d1 100644
--- a/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.rs
+++ b/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 
 fn id(
diff --git a/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.stderr b/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.stderr
index a9d649b82852..f162806cca3d 100644
--- a/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.stderr
+++ b/tests/ui/higher-ranked/trait-bounds/hang-on-deeply-nested-dyn.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/hang-on-deeply-nested-dyn.rs:12:5
+  --> $DIR/hang-on-deeply-nested-dyn.rs:13:5
    |
 LL |   ) -> &dyn Fn(
    |  ______-
diff --git a/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr b/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr
index f32ba57200d5..957082b6010c 100644
--- a/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr
+++ b/tests/ui/higher-ranked/trait-bounds/issue-30786.stderr
@@ -31,7 +31,6 @@ LL | pub struct Filter<S, F> {
 LL |     let count = filter.countx();
    |                        ^^^^^^ method cannot be called due to unsatisfied trait bounds
    |
-   = note: the full type name has been written to '$TEST_BUILD_DIR/higher-ranked/trait-bounds/issue-30786/issue-30786.long-type-hash.txt'
 note: the following trait bounds were not satisfied:
       `&'a mut &Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:131:30: 131:37]>: Stream`
       `&'a mut &mut Filter<Map<Repeat, for<'a> fn(&'a u64) -> &'a u64 {identity::<u64>}>, [closure@$DIR/issue-30786.rs:131:30: 131:37]>: Stream`
diff --git a/tests/ui/issues/issue-20413.rs b/tests/ui/issues/issue-20413.rs
index 4de22f0c9177..64d8cdc3e6f1 100644
--- a/tests/ui/issues/issue-20413.rs
+++ b/tests/ui/issues/issue-20413.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 trait Foo {
     fn answer(self);
diff --git a/tests/ui/issues/issue-20413.stderr b/tests/ui/issues/issue-20413.stderr
index 8891a26784e4..8d660478a31e 100644
--- a/tests/ui/issues/issue-20413.stderr
+++ b/tests/ui/issues/issue-20413.stderr
@@ -1,5 +1,5 @@
 error[E0392]: parameter `T` is never used
-  --> $DIR/issue-20413.rs:6:15
+  --> $DIR/issue-20413.rs:7:15
    |
 LL | struct NoData<T>;
    |               ^ unused parameter
@@ -8,14 +8,14 @@ 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<...>>>>>>>: Foo`
-  --> $DIR/issue-20413.rs:9:36
+  --> $DIR/issue-20413.rs:10:36
    |
 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<...>>>>>>>>>>>>>` to implement `Foo`
-  --> $DIR/issue-20413.rs:9:9
+  --> $DIR/issue-20413.rs:10:9
    |
 LL | impl<T> Foo for T where NoData<T>: Foo {
    |         ^^^     ^                  --- unsatisfied trait bound introduced here
@@ -24,20 +24,20 @@ LL | impl<T> Foo for T where NoData<T>: Foo {
    = note: required for `NoData<T>` to implement `Foo`
 
 error[E0275]: overflow evaluating the requirement `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<...>>>>>>>: Bar`
-  --> $DIR/issue-20413.rs:28:42
+  --> $DIR/issue-20413.rs:29:42
    |
 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 `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<...>>>>>>>` to implement `Baz`
-  --> $DIR/issue-20413.rs:35:9
+  --> $DIR/issue-20413.rs:36:9
    |
 LL | impl<T> Baz for T where AlmostNoData<T>: Bar {
    |         ^^^     ^                        --- unsatisfied trait bound introduced here
    = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
 note: required for `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<...>>>>>>>` to implement `Bar`
-  --> $DIR/issue-20413.rs:28:9
+  --> $DIR/issue-20413.rs:29:9
    |
 LL | impl<T> Bar for T where EvenLessData<T>: Baz {
    |         ^^^     ^                        --- unsatisfied trait bound introduced here
@@ -46,20 +46,20 @@ LL | impl<T> Bar for T where EvenLessData<T>: Baz {
    = note: required for `EvenLessData<T>` to implement `Baz`
 
 error[E0275]: overflow evaluating the requirement `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<...>>>>>>>: Baz`
-  --> $DIR/issue-20413.rs:35:42
+  --> $DIR/issue-20413.rs:36:42
    |
 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 `AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<...>>>>>>>` to implement `Bar`
-  --> $DIR/issue-20413.rs:28:9
+  --> $DIR/issue-20413.rs:29:9
    |
 LL | impl<T> Bar for T where EvenLessData<T>: Baz {
    |         ^^^     ^                        --- unsatisfied trait bound introduced here
    = note: the full type name has been written to '$TEST_BUILD_DIR/issues/issue-20413/issue-20413.long-type-hash.txt'
 note: required for `EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<AlmostNoData<EvenLessData<...>>>>>>>` to implement `Baz`
-  --> $DIR/issue-20413.rs:35:9
+  --> $DIR/issue-20413.rs:36:9
    |
 LL | impl<T> Baz for T where AlmostNoData<T>: Bar {
    |         ^^^     ^                        --- unsatisfied trait bound introduced here
diff --git a/tests/ui/issues/issue-23122-2.rs b/tests/ui/issues/issue-23122-2.rs
index 338789c2e871..06cd17ad1ead 100644
--- a/tests/ui/issues/issue-23122-2.rs
+++ b/tests/ui/issues/issue-23122-2.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 trait Next {
     type Next: Next;
diff --git a/tests/ui/issues/issue-23122-2.stderr b/tests/ui/issues/issue-23122-2.stderr
index 06e5b711a822..fe6b44de85b3 100644
--- a/tests/ui/issues/issue-23122-2.stderr
+++ b/tests/ui/issues/issue-23122-2.stderr
@@ -1,12 +1,12 @@
 error[E0275]: overflow evaluating the requirement `<<<<<<<... as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next: Sized`
-  --> $DIR/issue-23122-2.rs:11:17
+  --> $DIR/issue-23122-2.rs:12:17
    |
 LL |     type Next = <GetNext<T::Next> as Next>::Next;
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`issue_23122_2`)
 note: required for `GetNext<<<<<<<... as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next as Next>::Next>` to implement `Next`
-  --> $DIR/issue-23122-2.rs:10:15
+  --> $DIR/issue-23122-2.rs:11:15
    |
 LL | impl<T: Next> Next for GetNext<T> {
    |      -        ^^^^     ^^^^^^^^^^
diff --git a/tests/ui/issues/issue-37311-type-length-limit/issue-37311.rs b/tests/ui/issues/issue-37311-type-length-limit/issue-37311.rs
index c109be005238..372a641c5338 100644
--- a/tests/ui/issues/issue-37311-type-length-limit/issue-37311.rs
+++ b/tests/ui/issues/issue-37311-type-length-limit/issue-37311.rs
@@ -1,4 +1,5 @@
 // build-fail
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: ".nll/" -> "/"
 // ignore-compare-mode-next-solver (hangs)
 
diff --git a/tests/ui/issues/issue-37311-type-length-limit/issue-37311.stderr b/tests/ui/issues/issue-37311-type-length-limit/issue-37311.stderr
index 87832dd29b28..494da0ffa66d 100644
--- a/tests/ui/issues/issue-37311-type-length-limit/issue-37311.stderr
+++ b/tests/ui/issues/issue-37311-type-length-limit/issue-37311.stderr
@@ -1,11 +1,11 @@
 error: reached the recursion limit while instantiating `<(&(&(..., ...), ...), ...) as Foo>::recurse`
-  --> $DIR/issue-37311.rs:18:9
+  --> $DIR/issue-37311.rs:19:9
    |
 LL |         (self, self).recurse();
    |         ^^^^^^^^^^^^^^^^^^^^^^
    |
 note: `<T as Foo>::recurse` defined here
-  --> $DIR/issue-37311.rs:17:5
+  --> $DIR/issue-37311.rs:18:5
    |
 LL |     fn recurse(&self) {
    |     ^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/methods/inherent-bound-in-probe.rs b/tests/ui/methods/inherent-bound-in-probe.rs
index 81a99ca010e5..26be90202e68 100644
--- a/tests/ui/methods/inherent-bound-in-probe.rs
+++ b/tests/ui/methods/inherent-bound-in-probe.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 
 // Fixes #110131
diff --git a/tests/ui/methods/inherent-bound-in-probe.stderr b/tests/ui/methods/inherent-bound-in-probe.stderr
index ff03a7edb054..7632373eafe6 100644
--- a/tests/ui/methods/inherent-bound-in-probe.stderr
+++ b/tests/ui/methods/inherent-bound-in-probe.stderr
@@ -1,5 +1,5 @@
 error[E0277]: `Helper<'a, T>` is not an iterator
-  --> $DIR/inherent-bound-in-probe.rs:40:21
+  --> $DIR/inherent-bound-in-probe.rs:41:21
    |
 LL |     type IntoIter = Helper<'a, T>;
    |                     ^^^^^^^^^^^^^ `Helper<'a, T>` is not an iterator
@@ -9,14 +9,14 @@ note: required by a bound in `std::iter::IntoIterator::IntoIter`
   --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
 
 error[E0275]: overflow evaluating the requirement `&_: IntoIterator`
-  --> $DIR/inherent-bound-in-probe.rs:44:17
+  --> $DIR/inherent-bound-in-probe.rs:45:17
    |
 LL |         Helper::new(&self.0)
    |                 ^^^
    |
    = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`inherent_bound_in_probe`)
 note: required for `&BitReaderWrapper<_>` to implement `IntoIterator`
-  --> $DIR/inherent-bound-in-probe.rs:34:13
+  --> $DIR/inherent-bound-in-probe.rs:35:13
    |
 LL | impl<'a, T> IntoIterator for &'a BitReaderWrapper<T>
    |             ^^^^^^^^^^^^     ^^^^^^^^^^^^^^^^^^^^^^^
@@ -27,7 +27,7 @@ LL |     &'a T: IntoIterator<Item = &'a u8>,
    = note: required for `&BitReaderWrapper<BitReaderWrapper<BitReaderWrapper<BitReaderWrapper<BitReaderWrapper<...>>>>>` to implement `IntoIterator`
    = note: the full type name has been written to '$TEST_BUILD_DIR/methods/inherent-bound-in-probe/inherent-bound-in-probe.long-type-hash.txt'
 note: required by a bound in `Helper<'a, T>`
-  --> $DIR/inherent-bound-in-probe.rs:25:25
+  --> $DIR/inherent-bound-in-probe.rs:26:25
    |
 LL |     &'a T: IntoIterator<Item = &'a u8>,
    |                         ^^^^^^^^^^^^^ required by this bound in `Helper<'a, T>`
diff --git a/tests/ui/recursion/issue-83150.rs b/tests/ui/recursion/issue-83150.rs
index 75dcdc59f21c..67c3780ba20d 100644
--- a/tests/ui/recursion/issue-83150.rs
+++ b/tests/ui/recursion/issue-83150.rs
@@ -1,5 +1,5 @@
 // build-fail
-// compile-flags: -Copt-level=0
+// compile-flags: -Copt-level=0 -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 //~^^^ ERROR overflow evaluating the requirement
 // ignore-compare-mode-next-solver (hangs)
diff --git a/tests/ui/regions/issue-102374.rs b/tests/ui/regions/issue-102374.rs
index fd71248d9cb4..c8c22c48af1e 100644
--- a/tests/ui/regions/issue-102374.rs
+++ b/tests/ui/regions/issue-102374.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Zwrite-long-types-to-disk=yes
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"
 use std::cell::Cell;
 
diff --git a/tests/ui/regions/issue-102374.stderr b/tests/ui/regions/issue-102374.stderr
index af64b6867bb0..7a09ba05239d 100644
--- a/tests/ui/regions/issue-102374.stderr
+++ b/tests/ui/regions/issue-102374.stderr
@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-102374.rs:17:5
+  --> $DIR/issue-102374.rs:18:5
    |
 LL | ) -> i32 {
    |      --- expected `i32` because of return type
diff --git a/tests/ui/traits/issue-91949-hangs-on-recursion.rs b/tests/ui/traits/issue-91949-hangs-on-recursion.rs
index 312d5d08c7df..4a18ae5053f9 100644
--- a/tests/ui/traits/issue-91949-hangs-on-recursion.rs
+++ b/tests/ui/traits/issue-91949-hangs-on-recursion.rs
@@ -1,5 +1,5 @@
 // build-fail
-// compile-flags: -Zinline-mir=no
+// compile-flags: -Zinline-mir=no -Zwrite-long-types-to-disk=yes
 // error-pattern: overflow evaluating the requirement `<std::iter::Empty<()> as Iterator>::Item == ()`
 // error-pattern: function cannot return without recursing
 // normalize-stderr-test: "long-type-\d+" -> "long-type-hash"