Auto merge of rust-lang#118534 - RalfJung:extern-type-size-of-val, r=WaffleLapkin

codegen: panic when trying to compute size/align of extern type

The alignment is also computed when accessing a field of extern type at non-zero offset, so we also panic in that case.

Previously `size_of_val` worked because the code path there assumed that "thin pointer" means "sized". But that's not true any more with extern types. The returned size and align are just blatantly wrong, so it seems better to panic than returning wrong results. We use a non-unwinding panic since code probably does not expect size_of_val to panic.

Author: bors

build_system/tests.rs

@@ -75,11 +75,6 @@ const BASE_SYSROOT_SUITE: &[TestCase] = &[
         "example/arbitrary_self_types_pointers_and_wrappers.rs",
         &[],
     ),
-    TestCase::build_bin_and_run(
-        "aot.issue_91827_extern_types",
-        "example/issue-91827-extern-types.rs",
-        &[],
-    ),
     TestCase::build_lib("build.alloc_system", "example/alloc_system.rs", "lib"),
     TestCase::build_bin_and_run("aot.alloc_example", "example/alloc_example.rs", &[]),
     TestCase::jit_bin("jit.std_example", "example/std_example.rs", ""),