read_ref doe not need to mutate

thanks to @amosonn!

diff --git a/ralf/_posts/2018-04-05-a-formal-look-at-pinning.md b/ralf/_posts/2018-04-05-a-formal-look-at-pinning.md
index 72dccc18d5cbea0fd8931830160fb8335643dab3..5e51e7c747dbc01a0307a5f343b28e21cd27997c 100644 (file)
--- a/ralf/_posts/2018-04-05-a-formal-look-at-pinning.md
+++ b/ralf/_posts/2018-04-05-a-formal-look-at-pinning.md
@@ -68,11 +68,11 @@ impl SelfReferential {
     fn init(mut self: Pin<SelfReferential>) {
         let this : &mut SelfReferential = unsafe { Pin::get_mut(&mut self) };
         // Set up self_ref to point to this.data.
     fn init(mut self: Pin<SelfReferential>) {
         let this : &mut SelfReferential = unsafe { Pin::get_mut(&mut self) };
         // Set up self_ref to point to this.data.

-        this.self_ref = &mut this.data as *const i32;
+        this.self_ref = &this.data as *const i32;

     }
 
     }
 

-    fn read_ref(mut self: Pin<SelfReferential>) -> Option<i32> {
-        let this : &mut SelfReferential = unsafe { Pin::get_mut(&mut self) };
+    fn read_ref(self: Pin<SelfReferential>) -> Option<i32> {
+        let this : &SelfReferential = &*self;

         // Dereference self_ref if it is non-NULL.
         if this.self_ref == ptr::null() {
             None
         // Dereference self_ref if it is non-NULL.
         if this.self_ref == ptr::null() {
             None