flake: remove redundant transitive dependencies (tweag#1986)

* flake: remove redundant transitive dependencies

- add several more `follows` relationships for de-duplication

- update to latest rust-overlay flake which drops flake-utils dependency

- set `follows = ""` for a few unused dependencies.
    See NixOS/nix#7807

* delete `follows = ""` hacks

* delete one more `follows = ""` hack

* Fix new clippy 1.79 errors

---------

Co-authored-by: Yann Hamdaoui <[email protected]>

core/src/error/suggest.rs

@@ -24,7 +24,7 @@ where
     S: AsRef<str>,
     I: AsRef<str>,
 {
-    let mut max = std::f64::MIN;
+    let mut max = f64::MIN;
     let mut arg_max: Option<&'syms str> = None;
 
     if symbols.is_empty() {

core/src/identifier.rs

@@ -301,7 +301,9 @@ mod interner {
             // deallocation, so references are valid until the arena drop, which is tied to the
             // struct drop.
             let in_string = unsafe {
-                std::mem::transmute(self.arena.lock().unwrap().alloc_str(string.as_ref()))
+                std::mem::transmute::<&'_ str, &'a str>(
+                    self.arena.lock().unwrap().alloc_str(string.as_ref()),
+                )
             };
             let sym = Symbol(self.vec.len() as u32);
             self.vec.push(in_string);

core/src/nix_ffi/mod.rs

@@ -1,4 +1,3 @@
-#![cfg(feature = "nix-experimental")]
 #[cxx::bridge]
 mod internal {
     unsafe extern "C++" {

core/src/parser/utils.rs

@@ -654,7 +654,7 @@ pub fn mk_fun(pat: Pattern, body: RichTerm) -> Term {
 /// either a space or a tab, counted from the beginning of the line. If a line is empty or consist
 /// only of whitespace characters, it is ignored.
 pub fn min_indent(chunks: &[StrChunk<RichTerm>]) -> usize {
-    let mut min: usize = std::usize::MAX;
+    let mut min: usize = usize::MAX;
     let mut current = 0;
     let mut start_line = true;
 

flake.nix

@@ -9,17 +9,28 @@
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
-      inputs.flake-utils.follows = "flake-utils";
     };
     crane = {
       url = "github:ipetkov/crane";
       inputs.nixpkgs.follows = "nixpkgs";
     };
     topiary = {
       url = "github:tweag/topiary";
-      inputs.nixpkgs.follows = "nixpkgs";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        crane.follows = "crane";
+        flake-utils.follows = "flake-utils";
+        rust-overlay.follows = "rust-overlay";
+      };
+    };
+    nix-input = {
+      url = "github:nixos/nix";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-compat.follows = "pre-commit-hooks/flake-compat";
+        pre-commit-hooks.follows = "pre-commit-hooks";
+      };
     };
-    nix-input.url = "github:nixos/nix";
   };
 
   nixConfig = {