Auto merge of #1985 - RalfJung:fn-ptr, r=RalfJung

update fn ptr tests

This adjusts the tests for rust-lang/rust#94343.

rust-version

@@ -1 +1 @@
-3d127e2040b57157936f5f24e114a8b4c9a505ef
+9f8f0a6e9484fe25517c082a5cbe1e9edb17c8a8

src/diagnostics.rs

@@ -254,7 +254,7 @@ fn report_msg<'tcx>(
 ) {
     let span = stacktrace.first().map_or(DUMMY_SP, |fi| fi.span);
     let mut err = match diag_level {
-        DiagLevel::Error => tcx.sess.struct_span_err(span, title),
+        DiagLevel::Error => tcx.sess.struct_span_err(span, title).forget_guarantee(),
         DiagLevel::Warning => tcx.sess.struct_span_warn(span, title),
         DiagLevel::Note => tcx.sess.diagnostic().span_note_diag(span, title),
     };

tests/compile-fail/validity/invalid_fnptr_null.rs

@@ -1,5 +1,5 @@
 #![allow(invalid_value)]
 
 fn main() {
-    let _b: fn() = unsafe { std::mem::transmute(0usize) }; //~ ERROR encountered a potentially null function pointer
+    let _b: fn() = unsafe { std::mem::transmute(0usize) }; //~ ERROR encountered a null function pointer
 }

tests/run-pass/function_pointers.rs

@@ -62,9 +62,10 @@ fn main() {
     // Any non-null value is okay for function pointers.
     unsafe {
         let _x: fn() = mem::transmute(1usize);
-        let mut b = Box::new(42);
-        let ptr = &mut *b as *mut _;
+        let mut b = Box::new(42u8);
+        let ptr = &mut *b as *mut u8;
         drop(b);
         let _x: fn() = mem::transmute(ptr);
+        let _x: fn() = mem::transmute(ptr.wrapping_offset(1));
     }
 }