compare with-flag to without-flag

Author: RalfJung

src/test/ui/consts/extra-const-ub/detect-extra-ub.rs

@@ -1,36 +1,38 @@
-// compile-flags: -Zextra-const-ub-checks
+// revisions: no_flag with_flag
+// [no_flag] check-pass
+// [with_flag] compile-flags: -Zextra-const-ub-checks
 #![feature(const_ptr_read)]
 
 use std::mem::transmute;
 
 const INVALID_BOOL: () = unsafe {
     let _x: bool = transmute(3u8);
-    //~^ ERROR: evaluation of constant value failed
-    //~| invalid value
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
 };
 
 const INVALID_PTR_IN_INT: () = unsafe {
     let _x: usize = transmute(&3u8);
-    //~^ ERROR: evaluation of constant value failed
-    //~| invalid value
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
 };
 
 const INVALID_SLICE_TO_USIZE_TRANSMUTE: () = unsafe {
     let x: &[u8] = &[0; 32];
     let _x: (usize, usize) = transmute(x);
-    //~^ ERROR: evaluation of constant value failed
-    //~| invalid value
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
 };
 
 const UNALIGNED_PTR: () = unsafe {
     let _x: &u32 = transmute(&[0u8; 4]);
-    //~^ ERROR: evaluation of constant value failed
-    //~| invalid value
+    //[with_flag]~^ ERROR: evaluation of constant value failed
+    //[with_flag]~| invalid value
 };
 
 const UNALIGNED_READ: () = {
-    INNER; //~ERROR any use of this value will cause an error
-    //~| previously accepted
+    INNER; //[with_flag]~ERROR any use of this value will cause an error
+    //[with_flag]~| previously accepted
     // There is an error here but its span is in the standard library so we cannot match it...
     // so we have this in a *nested* const, such that the *outer* const fails to use it.
     const INNER: () = unsafe {

src/test/ui/consts/extra-const-ub/detect-extra-ub.stderr src/test/ui/consts/extra-const-ub/detect-extra-ub.with_flag.stderr

@@ -1,23 +1,23 @@
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:7:20
+  --> $DIR/detect-extra-ub.rs:9:20
    |
 LL |     let _x: bool = transmute(3u8);
    |                    ^^^^^^^^^^^^^^ constructing invalid value: encountered 0x03, but expected a boolean
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:13:21
+  --> $DIR/detect-extra-ub.rs:15:21
    |
 LL |     let _x: usize = transmute(&3u8);
    |                     ^^^^^^^^^^^^^^^ constructing invalid value: encountered (potentially part of) a pointer, but expected plain (non-pointer) bytes
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:20:30
+  --> $DIR/detect-extra-ub.rs:22:30
    |
 LL |     let _x: (usize, usize) = transmute(x);
    |                              ^^^^^^^^^^^^ constructing invalid value at .0: encountered (potentially part of) a pointer, but expected plain (non-pointer) bytes
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/detect-extra-ub.rs:26:20
+  --> $DIR/detect-extra-ub.rs:28:20
    |
 LL |     let _x: &u32 = transmute(&[0u8; 4]);
    |                    ^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered an unaligned reference (required 4 byte alignment but found 1)
@@ -36,13 +36,13 @@ LL |         copy_nonoverlapping(src, tmp.as_mut_ptr(), 1);
 LL |         unsafe { read(self) }
    |                  ---------- inside `ptr::const_ptr::<impl *const u32>::read` at $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
    |
-  ::: $DIR/detect-extra-ub.rs:39:9
+  ::: $DIR/detect-extra-ub.rs:41:9
    |
 LL |         ptr.read();
-   |         ---------- inside `INNER` at $DIR/detect-extra-ub.rs:39:9
+   |         ---------- inside `INNER` at $DIR/detect-extra-ub.rs:41:9
 
 error: any use of this value will cause an error
-  --> $DIR/detect-extra-ub.rs:32:5
+  --> $DIR/detect-extra-ub.rs:34:5
    |
 LL | const UNALIGNED_READ: () = {
    | ------------------------
@@ -58,7 +58,7 @@ error: aborting due to 6 previous errors
 For more information about this error, try `rustc --explain E0080`.
 Future incompatibility report: Future breakage diagnostic:
 error: any use of this value will cause an error
-  --> $DIR/detect-extra-ub.rs:32:5
+  --> $DIR/detect-extra-ub.rs:34:5
    |
 LL | const UNALIGNED_READ: () = {
    | ------------------------