Remove code duplication

crates/ra_syntax/src/ast.rs

@@ -42,11 +42,6 @@ pub trait AstNode {
     fn syntax(&self) -> &SyntaxNode;
 }
 
-#[test]
-fn assert_ast_is_object_safe() {
-    fn _f(_: &dyn AstNode, _: &dyn NameOwner) {}
-}
-
 /// Like `AstNode`, but wraps tokens rather than interior nodes.
 pub trait AstToken {
     fn can_cast(token: SyntaxKind) -> bool
@@ -64,22 +59,6 @@ pub trait AstToken {
     }
 }
 
-mod support {
-    use super::{AstChildren, AstNode, AstToken, SyntaxNode};
-
-    pub(super) fn child<N: AstNode>(parent: &SyntaxNode) -> Option<N> {
-        parent.children().find_map(N::cast)
-    }
-
-    pub(super) fn children<N: AstNode>(parent: &SyntaxNode) -> AstChildren<N> {
-        AstChildren::new(parent)
-    }
-
-    pub(super) fn token<T: AstToken>(parent: &SyntaxNode) -> Option<T> {
-        parent.children_with_tokens().filter_map(|it| it.into_token()).find_map(T::cast)
-    }
-}
-
 /// An iterator over `SyntaxNode` children of a particular AST type.
 #[derive(Debug, Clone)]
 pub struct AstChildren<N> {
@@ -100,12 +79,25 @@ impl<N: AstNode> Iterator for AstChildren<N> {
     }
 }
 
-fn child_opt<P: AstNode + ?Sized, C: AstNode>(parent: &P) -> Option<C> {
-    children(parent).next()
+mod support {
+    use super::{AstChildren, AstNode, AstToken, SyntaxNode};
+
+    pub(super) fn child<N: AstNode>(parent: &SyntaxNode) -> Option<N> {
+        parent.children().find_map(N::cast)
+    }
+
+    pub(super) fn children<N: AstNode>(parent: &SyntaxNode) -> AstChildren<N> {
+        AstChildren::new(parent)
+    }
+
+    pub(super) fn token<T: AstToken>(parent: &SyntaxNode) -> Option<T> {
+        parent.children_with_tokens().filter_map(|it| it.into_token()).find_map(T::cast)
+    }
 }
 
-fn children<P: AstNode + ?Sized, C: AstNode>(parent: &P) -> AstChildren<C> {
-    AstChildren::new(parent.syntax())
+#[test]
+fn assert_ast_is_object_safe() {
+    fn _f(_: &dyn AstNode, _: &dyn NameOwner) {}
 }
 
 #[test]