fix rust linter errors

Summary: This fixes several  clippy::needless_return and clippy::empty_line_after_doc_comment errors.

Reviewed By: madgen

Differential Revision: D67517609

fbshipit-source-id: b5f9bf9f43bffc13475c172f3dda1087a919f755

hphp/hack/src/hackrs/ty/decl/folded.rs

@@ -64,7 +64,7 @@ pub struct FoldedElement {
 /// class B<Tb> extends A<Tb, int> {}
 /// class C extends B<string> {}
 /// ```
-
+///
 /// The method `A::test()` has the type `(function(Ta1, Ta2): void)` in the
 /// context of class `A`. However in the context of class `B`, it will have type
 /// `(function(Tb, int): void)`.

hphp/hack/src/parser/core/declaration_parser.rs

@@ -1571,10 +1571,10 @@ where
         let token_kind = self.peek_token_kind();
         if token_kind == TokenKind::Readonly {
             let token = self.next_token();
-            return self.sc_mut().make_token(token);
+            self.sc_mut().make_token(token)
         } else {
             let pos = self.pos();
-            return self.sc_mut().make_missing(pos);
+            self.sc_mut().make_missing(pos)
         }
     }
 

hphp/hack/src/parser/lowerer/lowerer.rs

@@ -3756,55 +3756,55 @@ fn is_polymorphic_context<'a>(env: &mut Env<'a>, hint: &ast::Hint, ignore_this:
 
 fn has_polymorphic_context<'a>(env: &mut Env<'a>, contexts: Option<&ast::Contexts>) -> bool {
     if let Some(ast::Contexts(_, ref context_hints)) = contexts {
-        return context_hints
+        context_hints
             .iter()
-            .any(|c| is_polymorphic_context(env, c, false));
+            .any(|c| is_polymorphic_context(env, c, false))
     } else {
         false
     }
 }
 
 fn has_any_policied_context(contexts: Option<&ast::Contexts>) -> bool {
     if let Some(ast::Contexts(_, ref context_hints)) = contexts {
-        return context_hints.iter().any(|hint| match &*hint.1 {
+        context_hints.iter().any(|hint| match &*hint.1 {
             ast::Hint_::Happly(ast::Id(_, id), _) => sn::coeffects::is_any_zoned(id),
             _ => false,
-        });
+        })
     } else {
         false
     }
 }
 
 fn has_any_policied_or_defaults_context(contexts: Option<&ast::Contexts>) -> bool {
     if let Some(ast::Contexts(_, ref context_hints)) = contexts {
-        return context_hints.iter().any(|hint| match &*hint.1 {
+        context_hints.iter().any(|hint| match &*hint.1 {
             ast::Hint_::Happly(ast::Id(_, id), _) => sn::coeffects::is_any_zoned_or_defaults(id),
             _ => false,
-        });
+        })
     } else {
         true
     }
 }
 
 fn has_any_context(haystack: Option<&ast::Contexts>, needles: Vec<&str>) -> bool {
     if let Some(ast::Contexts(_, ref context_hints)) = haystack {
-        return context_hints.iter().any(|hint| match &*hint.1 {
+        context_hints.iter().any(|hint| match &*hint.1 {
             ast::Hint_::Happly(ast::Id(_, id), _) => needles.iter().any(|&context| id == context),
             _ => false,
-        });
+        })
     } else {
         true
     }
 }
 
 fn contexts_cannot_access_ic(haystack: Option<&ast::Contexts>) -> bool {
     if let Some(ast::Contexts(_, ref context_hints)) = haystack {
-        return context_hints.iter().all(|hint| match &*hint.1 {
+        context_hints.iter().all(|hint| match &*hint.1 {
             ast::Hint_::Happly(ast::Id(_, id), _) => {
                 sn::coeffects::is_any_without_implicit_policy_or_unsafe(id)
             }
             _ => false,
-        });
+        })
     } else {
         false // no context list -> implicit [defaults]
     }