src/Sema.zig                                                                  | 202 +++++++++++++++++++++++++++-----
 test/behavior/union.zig                                                       |  45 +++++++
 test/cases/compile_errors/noreturn_struct_field.zig                           |  12 ++
 test/cases/compile_errors/runtime_cast_to_union_which_has_non-void_fields.zig |   2 -
 test/cases/compile_errors/union_noreturn_field_initialized.zig                |  43 +++++++
 5 files changed, 270 insertions(+), 34 deletions(-)