Better pretty printing for const raw pointers

Author: iwikal

src/librustc/ty/print/pretty.rs

@@ -919,7 +919,10 @@ pub trait PrettyPrinter<'tcx>:
             },
             (ConstValue::Scalar(Scalar::Raw { data, .. }), ty::Char) =>
                 p!(write("{:?}", ::std::char::from_u32(data as u32).unwrap())),
-            (ConstValue::Scalar(_), ty::RawPtr(_)) => p!(write("{{pointer}}")),
+            (ConstValue::Scalar(Scalar::Raw { data, size }), ty::RawPtr(_)) => {
+                p!(write("{:#01$x} ", data, size as usize * 2));
+                self = self.pretty_print_type(&ct.ty)?;
+            }
             (ConstValue::Scalar(Scalar::Ptr(ptr)), ty::FnPtr(_)) => {
                 let instance = {
                     let alloc_map = self.tcx().alloc_map.lock();

src/test/ui/const-generics/raw-ptr-const-param.stderr

@@ -10,10 +10,10 @@ error[E0308]: mismatched types
   --> $DIR/raw-ptr-const-param.rs:7:38
    |
 LL |     let _: Const<{15 as *const _}> = Const::<{10 as *const _}>;
-   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `{pointer}`, found `{pointer}`
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `0x0000000000000f *const u32`, found `0x0000000000000a *const u32`
    |
-   = note: expected type `Const<{pointer}>`
-              found type `Const<{pointer}>`
+   = note: expected type `Const<0x0000000000000f *const u32>`
+              found type `Const<0x0000000000000a *const u32>`
 
 error: aborting due to previous error