From 7841fc61d206fc511d0399151e92844269ab0f90 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Rakic?= <remy.rakic+github@gmail.com>
Date: Sun, 1 Sep 2024 11:31:54 +0000
Subject: [PATCH 1/2] Revert "Use a reduced recursion limit in the MIR
 inliner's cycle breaker"

This reverts commit 950437a035aa81cf2af3d8aebdf8d9b294c54395.
---
 compiler/rustc_mir_transform/src/inline/cycle.rs | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/compiler/rustc_mir_transform/src/inline/cycle.rs b/compiler/rustc_mir_transform/src/inline/cycle.rs
index 9828e90de883e..41b9fb2edd1ce 100644
--- a/compiler/rustc_mir_transform/src/inline/cycle.rs
+++ b/compiler/rustc_mir_transform/src/inline/cycle.rs
@@ -136,14 +136,6 @@ pub(crate) fn mir_callgraph_reachable<'tcx>(
         }
         false
     }
-    // FIXME(-Znext-solver): Remove this hack when trait solver overflow can return an error.
-    // In code like that pointed out in #128887, the type complexity we ask the solver to deal with
-    // grows as we recurse into the call graph. If we use the same recursion limit here and in the
-    // solver, the solver hits the limit first and emits a fatal error. But if we use a reduced
-    // limit, we will hit the limit first and give up on looking for inlining. And in any case,
-    // the default recursion limits are quite generous for us. If we need to recurse 64 times
-    // into the call graph, we're probably not going to find any useful MIR inlining.
-    let recursion_limit = tcx.recursion_limit() / 2;
     process(
         tcx,
         param_env,
@@ -152,7 +144,7 @@ pub(crate) fn mir_callgraph_reachable<'tcx>(
         &mut Vec::new(),
         &mut FxHashSet::default(),
         &mut FxHashMap::default(),
-        recursion_limit,
+        tcx.recursion_limit(),
     )
 }
 

From 9af460b12f87fc73138fb3847d49ffa2bac5bb41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Rakic?= <remy.rakic+github@gmail.com>
Date: Sun, 1 Sep 2024 12:40:40 +0000
Subject: [PATCH 2/2] Revert "Rollup merge of #129757 -
 saethlin:half-a-recursion, r=compiler-errors"

This reverts commit 6b9ed71c21b10fd53c653e91207f6a3bf67df962, reversing
changes made to 8c7a7e346be4cdf13e77ab4acbfb5ade819a4e60.
---
 tests/mir-opt/inline/type_overflow.rs | 32 ---------------------------
 1 file changed, 32 deletions(-)
 delete mode 100644 tests/mir-opt/inline/type_overflow.rs

diff --git a/tests/mir-opt/inline/type_overflow.rs b/tests/mir-opt/inline/type_overflow.rs
deleted file mode 100644
index bfd9e71b9e73f..0000000000000
--- a/tests/mir-opt/inline/type_overflow.rs
+++ /dev/null
@@ -1,32 +0,0 @@
-// This is a regression test for one of the problems in #128887; it checks that the
-// strategy in #129714 avoids trait solver overflows in this specific case.
-
-// skip-filecheck
-//@ compile-flags: -Zinline-mir
-
-pub trait Foo {
-    type Associated;
-    type Chain: Foo<Associated = Self::Associated>;
-}
-
-trait FooExt {
-    fn do_ext() {}
-}
-impl<T: Foo<Associated = f64>> FooExt for T {}
-
-#[allow(unconditional_recursion)]
-fn recurse<T: Foo<Associated = f64>>() {
-    T::do_ext();
-    recurse::<T::Chain>();
-}
-
-macro_rules! emit {
-    ($($m:ident)*) => {$(
-        pub fn $m<T: Foo<Associated = f64>>() {
-            recurse::<T>();
-        }
-    )*}
-}
-
-// Increase the chance of triggering the bug
-emit!(m00 m01 m02 m03 m04 m05 m06 m07 m08 m09 m10 m11 m12 m13 m14 m15 m16 m17 m18 m19);