remove from_forall

compiler/rustc_infer/src/infer/mod.rs

@@ -485,17 +485,6 @@ pub enum NllRegionVariableOrigin {
 
     Existential {
         name: Option<Symbol>,
-        /// If this is true, then this variable was created to represent a lifetime
-        /// bound in a `for` binder. For example, it might have been created to
-        /// represent the lifetime `'a` in a type like `for<'a> fn(&'a u32)`.
-        /// Such variables are created when we are trying to figure out if there
-        /// is any valid instantiation of `'a` that could fit into some scenario.
-        ///
-        /// This is used to inform error reporting: in the case that we are trying to
-        /// determine whether there is any valid instantiation of a `'a` variable that meets
-        /// some constraint C, we want to blame the "source" of that `for` type,
-        /// rather than blaming the source of the constraint C.
-        from_forall: bool,
     },
 }