diff --git a/compiler/rustc_typeck/src/check/coercion.rs b/compiler/rustc_typeck/src/check/coercion.rs index 208eb27c84406..e05d14289c348 100644 --- a/compiler/rustc_typeck/src/check/coercion.rs +++ b/compiler/rustc_typeck/src/check/coercion.rs @@ -941,6 +941,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { exprs.len() ); + // The following check fixes #88097, where the compiler erroneously + // attempted to coerce a closure type to itself via a function pointer. + if prev_ty == new_ty { + return Ok(prev_ty); + } + // Special-case that coercion alone cannot handle: // Function items or non-capturing closures of differing IDs or InternalSubsts. let (a_sig, b_sig) = { diff --git a/src/test/ui/coercion/issue-88097.rs b/src/test/ui/coercion/issue-88097.rs new file mode 100644 index 0000000000000..e543e1bae9239 --- /dev/null +++ b/src/test/ui/coercion/issue-88097.rs @@ -0,0 +1,31 @@ +// In #88097, the compiler attempted to coerce a closure type to itself via +// a function pointer, which caused an unnecessary error. Check that this +// behavior has been fixed. + +// check-pass + +fn peculiar() -> impl Fn(u8) -> u8 { + return |x| x + 1 +} + +fn peculiar2() -> impl Fn(u8) -> u8 { + return |x| x + 1; +} + +fn peculiar3() -> impl Fn(u8) -> u8 { + let f = |x| x + 1; + return f +} + +fn peculiar4() -> impl Fn(u8) -> u8 { + let f = |x| x + 1; + f +} + +fn peculiar5() -> impl Fn(u8) -> u8 { + let f = |x| x + 1; + let g = |x| x + 2; + return if true { f } else { g } +} + +fn main() {}