Add FIXME comments referencing rust-lang#6894 and rust-lang#8888

Author: brendanzab

src/libstd/num/mod.rs

@@ -344,7 +344,7 @@ pub trait Primitive: Clone
                    + Div<Self,Self>
                    + Rem<Self,Self> {
     // FIXME (#5527): These should be associated constants
-    // FIXME (#8888): Removing `unused_self` requires #8888 to be fixed.
+    // FIXME (#8888): `ForType` should be a language feature. See also: #6894
     fn bits(_: ForType<Self>) -> uint;
     fn bytes(_: ForType<Self>) -> uint;
     fn is_signed(_: ForType<Self>) -> bool;
@@ -388,7 +388,7 @@ pub trait Float: Real
     fn is_normal(&self) -> bool;
     fn classify(&self) -> FPCategory;
 
-    // FIXME (#8888): Removing `unused_self` requires #8888 to be fixed.
+    // FIXME (#8888): `ForType` should be a language feature. See also: #6894
     fn mantissa_digits(_: ForType<Self>) -> uint;
     fn digits(_: ForType<Self>) -> uint;
     fn epsilon() -> Self;

src/libstd/util.rs

@@ -96,6 +96,7 @@ impl Void {
 ///
 /// assert_eq!(A::a(ForType::<int>), 6);
 /// ~~~
+// FIXME (#8888): This should really be part of the language. See also: #6894
 pub struct ForType<T>;
 
 #[cfg(test)]
@@ -176,7 +177,7 @@ mod tests {
         }
 
         impl A for int {
-            fn a(_: ForType<int>) -> uint { 6 }
+            fn a(_: ForType<int33>) -> uint { 6 }
         }
 
         assert_eq!(A::a(ForType::<int>), 6);