Rollup merge of #124168 - oli-obk:define_opaque_types12, r=lcnr

Use `DefiningOpaqueTypes::Yes` in rustdoc, where the `InferCtxt` is guaranteed to have no opaque types it can define

r? `@lcnr`

I manually checked there it's always `tcx.infer_ctxt().build()`

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -784,7 +784,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
 
                     match (evaluate(c1), evaluate(c2)) {
                         (Ok(c1), Ok(c2)) => {
-                            match selcx.infcx.at(&obligation.cause, obligation.param_env).eq(DefineOpaqueTypes::No,c1, c2)
+                            match selcx.infcx.at(&obligation.cause, obligation.param_env).eq(DefineOpaqueTypes::Yes,c1, c2)
                             {
                                 Ok(_) => (),
                                 Err(_) => return false,