error: any use of this value will cause an error
  --> $DIR/union-ice.rs:23:1
   |
LL | const FIELD3: Field3 = unsafe { UNION.field3 }; //~ ERROR will cause an error
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempted to read undefined bytes
   |
   = note: #[deny(const_err)] on by default

error[E0080]: it is undefined behavior to use this value
  --> $DIR/union-ice.rs:25:1
   |
LL | / const FIELD_PATH: Struct = Struct { //~ ERROR it is undefined behavior to use this value
LL | |     a: 42,
LL | |     b: unsafe { UNION.field3 },
LL | | };
   | |__^ type validation failed: encountered uninitialized bytes at .b, but expected initialized plain bits
   |
   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior

error[E0080]: it is undefined behavior to use this value
  --> $DIR/union-ice.rs:35:1
   |
LL | / const FIELD_PATH2: Struct2 = Struct2 { //~ ERROR it is undefined behavior to use this value
LL | |     b: [
LL | |         21,
LL | |         unsafe { UNION.field3 },
...  |
LL | |     a: 42,
LL | | };
   | |__^ type validation failed: encountered undefined bytes at .b[1]
   |
   = note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0080`.