Fix ICE while computing type layout (#14837)

If a type is incomplete, for example if generic parameters are not
available yet, although they are not escaping, its layout may not be
computable. Calling `TyCtxt::layout_of()` would create a delayed bug in
the compiler.

changelog: [`zero_sized_map_values`]: fix ICE

Fixes rust-lang/rust-clippy#14822

r? @Jarcho

1 files changed, 5 insertions, 3 deletions

diff --git a/clippy_lints/src/zero_sized_map_values.rs b/clippy_lints/src/zero_sized_map_values.rs
index 24b1381ba45..1550872bca2 100644
--- a/clippy_lints/src/zero_sized_map_values.rs
+++ b/clippy_lints/src/zero_sized_map_values.rs
@@ -51,9 +51,11 @@ impl LateLintPass<'_> for ZeroSizedMapValues {
             && (is_type_diagnostic_item(cx, ty, sym::HashMap) || is_type_diagnostic_item(cx, ty, sym::BTreeMap))
             && let ty::Adt(_, args) = ty.kind()
             && let ty = args.type_at(1)
-            // Fixes https://github.com/rust-lang/rust-clippy/issues/7447 because of
-            // https://github.com/rust-lang/rust/blob/master/compiler/rustc_middle/src/ty/sty.rs#L968
-            && !ty.has_escaping_bound_vars()
+            // Ensure that no type information is missing, to avoid a delayed bug in the compiler if this is not the case.
+            // This might happen when computing a reference/pointer metadata on a type for which we
+            // cannot check if it is `Sized` or not, such as an incomplete associated type in a
+            // type alias. See an example in `issue14822()` of `tests/ui/zero_sized_hashmap_values.rs`.
+            && !ty.has_non_region_param()
             && let Ok(layout) = cx.layout_of(ty)
             && layout.is_zst()
         {