use TypingEnv when no infcx is available

the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -259,7 +259,9 @@ fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<()
                     let ty_a = field.ty(tcx, args_a);
                     let ty_b = field.ty(tcx, args_b);
 
-                    if let Ok(layout) = tcx.layout_of(param_env.and(ty_a)) {
+                    if let Ok(layout) =
+                        tcx.layout_of(infcx.typing_env(param_env).as_query_input(ty_a))
+                    {
                         if layout.is_1zst() {
                             // ignore 1-ZST fields
                             return false;