Address clippy lints on stable Rust

Cargo.toml

@@ -87,9 +87,11 @@ clippy.derivable_impls = "allow"
 clippy.field_reassign_with_default = "allow"
 clippy.get_first = "allow"
 clippy.if_same_then_else = "allow"
+clippy.len_without_is_empty = "allow"
 clippy.manual_is_ascii_check = "allow"
 clippy.mut_from_ref = "allow"
 clippy.needless_return = "allow"
+clippy.new_without_default = "allow"
 clippy.option_map_unit_fn = "allow"
 clippy.ptr_arg = "allow"
 clippy.redundant_slicing = "allow"

fish-rust/src/lib.rs

@@ -12,9 +12,11 @@
 #![allow(clippy::field_reassign_with_default)]
 #![allow(clippy::get_first)]
 #![allow(clippy::if_same_then_else)]
+#![allow(clippy::len_without_is_empty)]
 #![allow(clippy::manual_is_ascii_check)]
 #![allow(clippy::mut_from_ref)]
 #![allow(clippy::needless_return)]
+#![allow(clippy::new_without_default)]
 #![allow(clippy::option_map_unit_fn)]
 #![allow(clippy::ptr_arg)]
 #![allow(clippy::redundant_slicing)]

fish-rust/src/parse_tree.rs

@@ -162,14 +162,6 @@ impl<NodeType: Node> NodeRef<NodeType> {
     pub fn parsed_source_ref(&self) -> ParsedSourceRef {
         Pin::into_inner(self.parsed_source.clone())
     }
-
-    /// Construct a NodeRef from ParsedSource and a node, which must point into that parsed source.
-    pub unsafe fn from_parts(parsed_source: ParsedSourceRef, node: &NodeType) -> Self {
-        NodeRef {
-            parsed_source: Pin::new(parsed_source),
-            node: node as *const NodeType,
-        }
-    }
 }
 
 // Safety: NodeRef is Send and Sync because it's just a pointer into a parse tree, which is pinned.

fish-rust/src/threads.rs

@@ -487,7 +487,7 @@ pub fn iothread_service_main(ctx: &mut ReaderData) {
 }
 
 /// Does nasty polling via select() and marked as unsafe because it should only be used for testing.
-pub unsafe fn iothread_drain_all(ctx: &mut ReaderData) {
+pub(crate) unsafe fn iothread_drain_all(ctx: &mut ReaderData) {
     while borrow_io_thread_pool()
         .shared
         .mutex

fish-rust/src/wutil/dir_iter.rs

@@ -244,6 +244,7 @@ impl DirIter {
     /// Read the next entry in the directory.
     /// This returns an error if readir errors, or Ok(None) if there are no more entries; else an Ok entry.
     /// This is slightly more efficient than the Iterator version, as it avoids allocating.
+    #[allow(clippy::should_implement_trait)]
     pub fn next(&mut self) -> Option<io::Result<&DirEntry>> {
         errno::set_errno(errno::Errno(0));
         let dent = unsafe { libc::readdir(self.dir.dir()).as_ref() };