Pretty print raw pointers in consts as '{pointer}'.

src/librustc/ty/print/pretty.rs

@@ -919,6 +919,7 @@ fn pretty_print_const(
             },
             (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::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 `Scalar(0x000000000000000f) : *const u32`, found `Scalar(0x000000000000000a) : *const u32`
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^ expected `{pointer}`, found `{pointer}`
    |
-   = note: expected type `Const<Scalar(0x000000000000000f) : *const u32>`
-              found type `Const<Scalar(0x000000000000000a) : *const u32>`
+   = note: expected type `Const<{pointer}>`
+              found type `Const<{pointer}>`
 
 error: aborting due to previous error