Disable newly added CheckNull pass in clippy and miri

Author: 1c3t3a

src/tools/clippy/clippy_lints/src/missing_const_for_fn.rs

@@ -154,10 +154,10 @@ impl<'tcx> LateLintPass<'tcx> for MissingConstForFn {
             return;
         }
 
-        let mir = cx.tcx.mir_drops_elaborated_and_const_checked(def_id);
+        let mir = cx.tcx.optimized_mir(def_id);
 
-        if let Ok(()) = is_min_const_fn(cx.tcx,& mir.borrow(), &self.msrv)
-        && let hir::Node::Item(hir::Item { vis_span, .. }) | hir::Node::ImplItem(hir::ImplItem { vis_span, .. }) =
+        if let Ok(()) = is_min_const_fn(cx.tcx, &mir, &self.msrv)
+            && let hir::Node::Item(hir::Item { vis_span, .. }) | hir::Node::ImplItem(hir::ImplItem { vis_span, .. }) =
                 cx.tcx.hir_node_by_def_id(def_id)
         {
             let suggestion = if vis_span.is_empty() { "const " } else { " const" };

src/tools/clippy/src/driver.rs

@@ -166,6 +166,8 @@ impl rustc_driver::Callbacks for ClippyCallbacks {
         // MIR passes can be enabled / disabled separately, we should figure out, what passes to
         // use for Clippy.
         config.opts.unstable_opts.mir_opt_level = Some(0);
+        config.opts.unstable_opts.mir_enable_passes =
+            vec![("CheckNull".to_owned(), false)];
 
         // Disable flattening and inlining of format_args!(), so the HIR matches with the AST.
         config.opts.unstable_opts.flatten_format_args = false;

src/tools/miri/src/lib.rs

@@ -166,7 +166,7 @@ pub const MIRI_DEFAULT_ARGS: &[&str] = &[
     "-Zmir-emit-retag",
     "-Zmir-keep-place-mention",
     "-Zmir-opt-level=0",
-    "-Zmir-enable-passes=-CheckAlignment",
+    "-Zmir-enable-passes=-CheckAlignment,-CheckNull",
     // Deduplicating diagnostics means we miss events when tracking what happens during an
     // execution. Let's not do that.
     "-Zdeduplicate-diagnostics=no",

src/tools/miri/tests/fail/dangling_pointers/null_pointer_deref.rs

@@ -1,6 +1,3 @@
-// Enable the UB checks for the sake of this test.
-//@compile-flags: -Zub-checks=no
-
 #[allow(deref_nullptr)]
 fn main() {
     let x: i32 = unsafe { *std::ptr::null() }; //~ ERROR: null pointer

src/tools/miri/tests/fail/dangling_pointers/null_pointer_write.rs

@@ -1,6 +1,3 @@
-// Enable the UB checks for the sake of this test.
-//@compile-flags: -Zub-checks=no
-
 #[allow(deref_nullptr)]
 fn main() {
     unsafe { *std::ptr::null_mut() = 0i32 }; //~ ERROR: null pointer