Disallow compile warnings in CI

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
-      - run: cargo check ${{ matrix.features }}
+      - run: RUSTFLAGS="--deny warnings" cargo check ${{ matrix.features }}
 
   msrv:
     runs-on: ubuntu-latest

benches/fold_specialization.rs

@@ -1,3 +1,5 @@
+#![allow(unstable_name_collisions)]
+
 use criterion::{criterion_group, criterion_main, Criterion};
 use itertools::Itertools;
 

benches/tree_fold1.rs

@@ -1,3 +1,5 @@
+#![allow(deprecated)]
+
 use criterion::{criterion_group, criterion_main, Criterion};
 use itertools::{cloned, Itertools};
 

src/size_hint.rs

@@ -29,6 +29,7 @@ pub fn add_scalar(sh: SizeHint, x: usize) -> SizeHint {
 }
 
 /// Subtract `x` correctly from a `SizeHint`.
+#[cfg(feature = "use_alloc")]
 #[inline]
 pub fn sub_scalar(sh: SizeHint, x: usize) -> SizeHint {
     let (mut low, mut hi) = sh;

src/tuple_impl.rs

@@ -111,7 +111,7 @@ where
         // not yet produced as a tuple.
         let buffered = T::buffer_len(&self.buf);
         // To that, we must add the size estimates of the underlying iterator.
-        let (mut unbuffered_lo, mut unbuffered_hi) = self.iter.size_hint();
+        let (unbuffered_lo, unbuffered_hi) = self.iter.size_hint();
         // The total low estimate is the sum of the already-buffered elements,
         // plus the low estimate of remaining unbuffered elements, divided by
         // the tuple size.

tests/quick.rs

@@ -3,6 +3,8 @@
 //!
 //! In particular we test the tedious size_hint and exact size correctness.
 
+#![allow(deprecated, unstable_name_collisions)]
+
 use itertools::free::{
     cloned, enumerate, multipeek, peek_nth, put_back, put_back_n, rciter, zip, zip_eq,
 };

tests/specializations.rs

@@ -1,3 +1,5 @@
+#![allow(unstable_name_collisions)]
+
 use itertools::Itertools;
 use quickcheck::quickcheck;
 use std::fmt::Debug;

tests/test_core.rs

@@ -4,6 +4,7 @@
 //! option. This file may not be copied, modified, or distributed
 //! except according to those terms.
 #![no_std]
+#![allow(deprecated)]
 
 use crate::it::chain;
 use crate::it::free::put_back;

tests/test_std.rs

@@ -1,3 +1,5 @@
+#![allow(unstable_name_collisions)]
+
 use crate::it::cloned;
 use crate::it::free::put_back_n;
 use crate::it::free::rciter;