diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index b97e0a80fe6c9..00a684f296325 100644 --- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -1755,6 +1755,8 @@ fn check_variances_for_type_defn<'tcx>( .collect::>() }); + let ty_generics = tcx.generics_of(item.owner_id); + for (index, _) in variances.iter().enumerate() { let parameter = Parameter(index as u32); @@ -1762,13 +1764,27 @@ fn check_variances_for_type_defn<'tcx>( continue; } - let param = &hir_generics.params[index]; + let ty_param = &ty_generics.params[index]; + let hir_param = &hir_generics.params[index]; + + if ty_param.def_id != hir_param.def_id.into() { + // valid programs always have lifetimes before types in the generic parameter list + // ty_generics are normalized to be in this required order, and variances are built + // from ty generics, not from hir generics. but we need hir generics to get + // a span out + // + // if they aren't in the same order, then the user has written invalid code, and already + // got an error about it (or I'm wrong about this) + tcx.sess + .delay_span_bug(hir_param.span, "hir generics and ty generics in different order"); + continue; + } - match param.name { + match hir_param.name { hir::ParamName::Error => {} _ => { let has_explicit_bounds = explicitly_bounded_params.contains(¶meter); - report_bivariance(tcx, param, has_explicit_bounds); + report_bivariance(tcx, hir_param, has_explicit_bounds); } } } diff --git a/tests/ui/generics/issue-83556.rs b/tests/ui/generics/issue-83556.rs new file mode 100644 index 0000000000000..7cea1c8631fe9 --- /dev/null +++ b/tests/ui/generics/issue-83556.rs @@ -0,0 +1,4 @@ +struct Foo(&'a ()); +//~^ ERROR lifetime parameters must be declared prior to + +fn main() {} diff --git a/tests/ui/generics/issue-83556.stderr b/tests/ui/generics/issue-83556.stderr new file mode 100644 index 0000000000000..93affaffe60c3 --- /dev/null +++ b/tests/ui/generics/issue-83556.stderr @@ -0,0 +1,8 @@ +error: lifetime parameters must be declared prior to type and const parameters + --> $DIR/issue-83556.rs:1:15 + | +LL | struct Foo(&'a ()); + | ----^^- help: reorder the parameters: lifetimes, then consts and types: `<'a, T>` + +error: aborting due to previous error +