regression tests for problems that are exposed by mir-inlining policy…

… that we are reverting for 1.64-beta.
rust-lang · Aug 29, 2022 · 2f96703 · 2f96703
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diff --git a/src/test/ui/issues/issue-100550-normalization-ice-exposed-by-mir-inlining.rs b/src/test/ui/issues/issue-100550-normalization-ice-exposed-by-mir-inlining.rs
@@ -0,0 1,39 @@
 // check-pass
 
 // compile-flags: --emit=mir,link -O
 
 // There is an ICE somewhere in type normalization, and we are hitting it during
 // the MIR inlining pass on this code.
 //
 // Long term, we should fix that ICE and change the compile-flags for this test
 // to explicitly enable MIR inlining.
 //
 // Short term, we are diabling MIR inlining for Rust 1.64-beta, so that we avoid
 // this ICE in this instance.
 
 pub trait Trait {
  type Associated;
 }
 impl<T> Trait for T {
  type Associated = T;
 }
 
 pub struct Struct<T>(<T as Trait>::Associated);
 
 pub fn foo<T>() -> Struct<T>
 where
  T: Trait,
 {
  bar()
 }
 
 #[inline]
 fn bar<T>() -> Struct<T> {
  Struct(baz())
 }
 
 fn baz<T>() -> T {
  unimplemented!()
 }
 
 fn main() { }
diff --git a/src/test/ui/mir/issue-100476-recursion-check-blewup.rs b/src/test/ui/mir/issue-100476-recursion-check-blewup.rs
@@ -0,0 1,42 @@
 // check-pass
 
 // compile-flags: --emit=mir,link -O
 
 // At one point the MIR inlining, when guarding against infinitely (or even just
 // excessive) recursion, was using `ty::Instance` as the basis for its history
 // check. The problem is that when you have polymorphic recursion, you can have
 // distinct instances of the same code (because you're inlining the same code
 // with differing substitutions), causing the amount of inlining to blow up
 // exponentially.
 //
 // This test illustrates an example of that filed in issue rust#100476.
 
 #![allow(unconditional_recursion)]
 #![feature(decl_macro)]
 
 macro emit($($m:ident)*) {$(
  // Randomize `def_path_hash` by defining them under a module with
  // different names
  pub mod $m {
  pub trait Tr {
  type Next: Tr;
  }
 
  pub fn hoge<const N: usize, T: Tr>() {
  inner::<N, T>();
  }
 
  #[inline(always)]
  fn inner<const N: usize, T: Tr>() {
  inner::<N, T::Next>();
  }
  }
 )*}
 
 // 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
 );
 
 fn main() { }