ub-ref-ptr: check some more of the detailed error messages

Author: RalfJung

tests/ui/consts/const-eval/ub-ref-ptr.rs

@@ -22,9 +22,11 @@ const UNALIGNED_BOX: Box<u16> = unsafe { mem::transmute(&[0u8; 4]) };
 
 const NULL: &u16 = unsafe { mem::transmute(0usize) };
 //~^ ERROR it is undefined behavior to use this value
+//~| null reference
 
 const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
 //~^ ERROR it is undefined behavior to use this value
+//~| null box
 
 
 // It is very important that we reject this: We do promote `&(4 * REF_AS_USIZE)`,
@@ -41,23 +43,28 @@ const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize],
 
 const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
 //~^ ERROR it is undefined behavior to use this value
+//~| dangling reference
 
 const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
 //~^ ERROR it is undefined behavior to use this value
+//~| dangling box
 
 const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
 //~^ ERROR evaluation of constant value failed
 //~| uninitialized
 
 const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
 //~^ ERROR it is undefined behavior to use this value
+//~| encountered null pointer, but expected a function pointer
 const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
 //~^ ERROR evaluation of constant value failed
 //~| uninitialized
 const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
 //~^ ERROR it is undefined behavior to use this value
+//~| expected a function pointer
 const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
 //~^ ERROR it is undefined behavior to use this value
+//~| expected a function pointer
 
 
 const UNALIGNED_READ: () = unsafe {

tests/ui/consts/const-eval/ub-ref-ptr.stderr

@@ -32,7 +32,7 @@ LL | const NULL: &u16 = unsafe { mem::transmute(0usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:26:1
+  --> $DIR/ub-ref-ptr.rs:27:1
    |
 LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a null box
@@ -43,7 +43,7 @@ LL | const NULL_BOX: Box<u16> = unsafe { mem::transmute(0usize) };
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:33:1
+  --> $DIR/ub-ref-ptr.rs:35:1
    |
 LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into integer
@@ -52,7 +52,7 @@ LL | const REF_AS_USIZE: usize = unsafe { mem::transmute(&0) };
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:36:39
+  --> $DIR/ub-ref-ptr.rs:38:39
    |
 LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into integer
@@ -61,13 +61,13 @@ LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 note: erroneous constant encountered
-  --> $DIR/ub-ref-ptr.rs:36:38
+  --> $DIR/ub-ref-ptr.rs:38:38
    |
 LL | const REF_AS_USIZE_SLICE: &[usize] = &[unsafe { mem::transmute(&0) }];
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:39:86
+  --> $DIR/ub-ref-ptr.rs:41:86
    |
 LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
    |                                                                                      ^^^^^^^^^^^^^^^^^^^^ unable to turn pointer into integer
@@ -76,13 +76,13 @@ LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[us
    = help: the absolute address of a pointer is not known at compile-time, so such operations are not supported
 
 note: erroneous constant encountered
-  --> $DIR/ub-ref-ptr.rs:39:85
+  --> $DIR/ub-ref-ptr.rs:41:85
    |
 LL | const REF_AS_USIZE_BOX_SLICE: Box<[usize]> = unsafe { mem::transmute::<&[usize], _>(&[mem::transmute(&0)]) };
    |                                                                                     ^^^^^^^^^^^^^^^^^^^^^
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:42:1
+  --> $DIR/ub-ref-ptr.rs:44:1
    |
 LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling reference (0x539[noalloc] has no provenance)
@@ -93,7 +93,7 @@ LL | const USIZE_AS_REF: &'static u8 = unsafe { mem::transmute(1337usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:45:1
+  --> $DIR/ub-ref-ptr.rs:48:1
    |
 LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a dangling box (0x539[noalloc] has no provenance)
@@ -104,13 +104,13 @@ LL | const USIZE_AS_BOX: Box<u8> = unsafe { mem::transmute(1337usize) };
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:48:41
+  --> $DIR/ub-ref-ptr.rs:52:41
    |
 LL | const UNINIT_PTR: *const i32 = unsafe { MaybeUninit { uninit: () }.init };
    |                                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:52:1
+  --> $DIR/ub-ref-ptr.rs:56:1
    |
 LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered null pointer, but expected a function pointer
@@ -121,13 +121,13 @@ LL | const NULL_FN_PTR: fn() = unsafe { mem::transmute(0usize) };
            }
 
 error[E0080]: evaluation of constant value failed
-  --> $DIR/ub-ref-ptr.rs:54:38
+  --> $DIR/ub-ref-ptr.rs:59:38
    |
 LL | const UNINIT_FN_PTR: fn() = unsafe { MaybeUninit { uninit: () }.init };
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ using uninitialized data, but this operation requires initialized memory
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:57:1
+  --> $DIR/ub-ref-ptr.rs:62:1
    |
 LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered 0xd[noalloc], but expected a function pointer
@@ -138,7 +138,7 @@ LL | const DANGLING_FN_PTR: fn() = unsafe { mem::transmute(13usize) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:59:1
+  --> $DIR/ub-ref-ptr.rs:65:1
    |
 LL | const DATA_FN_PTR: fn() = unsafe { mem::transmute(&13) };
    | ^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered ALLOC2<imm>, but expected a function pointer
@@ -158,13 +158,13 @@ note: inside `std::ptr::read::<u32>`
 note: inside `std::ptr::const_ptr::<impl *const u32>::read`
   --> $SRC_DIR/core/src/ptr/const_ptr.rs:LL:COL
 note: inside `UNALIGNED_READ`
-  --> $DIR/ub-ref-ptr.rs:66:5
+  --> $DIR/ub-ref-ptr.rs:73:5
    |
 LL |     ptr.read();
    |     ^^^^^^^^^^
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:69:1
+  --> $DIR/ub-ref-ptr.rs:76:1
    |
 LL | const POINTS_TO_FUNCTION: &() = unsafe {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value: encountered a reference pointing to a function
@@ -175,7 +175,7 @@ LL | const POINTS_TO_FUNCTION: &() = unsafe {
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/ub-ref-ptr.rs:74:1
+  --> $DIR/ub-ref-ptr.rs:81:1
    |
 LL | const POINTS_TO_VTABLE: (&(), &()) = unsafe {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constructing invalid value at .1: encountered a reference pointing to a vtable