Auto merge of #11020 - Centri3:tuple_array_conversion, r=llogiq

New lint [`tuple_array_conversions`]

Closes #10748

PS, the implementation is a bit ugly :sweat_smile: ~~I will likely refactor soon enough :)~~ Done :D

changelog: New lint [`tuple_array_conversions`]

1 files changed, 73 insertions, 0 deletions

diff --git a/tests/ui/tuple_array_conversions.rs b/tests/ui/tuple_array_conversions.rs
new file mode 100644
index 00000000000..f96a7c97f1a
--- /dev/null
+++ b/tests/ui/tuple_array_conversions.rs
@@ -0,0 +1,73 @@
+//@aux-build:proc_macros.rs:proc-macro
+#![allow(clippy::no_effect, clippy::useless_vec, unused)]
+#![warn(clippy::tuple_array_conversions)]
+
+#[macro_use]
+extern crate proc_macros;
+
+fn main() {
+    let x = [1, 2];
+    let x = (x[0], x[1]);
+    let x = [x.0, x.1];
+    let x = &[1, 2];
+    let x = (x[0], x[1]);
+
+    let t1: &[(u32, u32)] = &[(1, 2), (3, 4)];
+    let v1: Vec<[u32; 2]> = t1.iter().map(|&(a, b)| [a, b]).collect();
+    t1.iter().for_each(|&(a, b)| _ = [a, b]);
+    let t2: Vec<(u32, u32)> = v1.iter().map(|&[a, b]| (a, b)).collect();
+    t1.iter().for_each(|&(a, b)| _ = [a, b]);
+    // Do not lint
+    let v2: Vec<[u32; 2]> = t1.iter().map(|&t| t.into()).collect();
+    let t3: Vec<(u32, u32)> = v2.iter().map(|&v| v.into()).collect();
+    let x = [1; 13];
+    let x = (
+        x[0], x[1], x[2], x[3], x[4], x[5], x[6], x[7], x[8], x[9], x[10], x[11], x[12],
+    );
+    let x = [x.0, x.1, x.2, x.3, x.4, x.5, x.6, x.7, x.8, x.9, x.10, x.11, x.12];
+    let x = (1, 2);
+    let x = (x.0, x.1);
+    let x = [1, 2];
+    let x = [x[0], x[1]];
+    let x = vec![1, 2];
+    let x = (x[0], x[1]);
+    let x = [1; 3];
+    let x = (x[0],);
+    let x = (1, 2, 3);
+    let x = [x.0];
+    let x = (1, 2);
+    let y = (1, 2);
+    [x.0, y.0];
+    [x.0, y.1];
+    let x = [x.0, x.0];
+    let x = (x[0], x[0]);
+    external! {
+        let t1: &[(u32, u32)] = &[(1, 2), (3, 4)];
+        let v1: Vec<[u32; 2]> = t1.iter().map(|&(a, b)| [a, b]).collect();
+        let t2: Vec<(u32, u32)> = v1.iter().map(|&[a, b]| (a, b)).collect();
+    }
+    with_span! {
+        span
+        let t1: &[(u32, u32)] = &[(1, 2), (3, 4)];
+        let v1: Vec<[u32; 2]> = t1.iter().map(|&(a, b)| [a, b]).collect();
+        let t2: Vec<(u32, u32)> = v1.iter().map(|&[a, b]| (a, b)).collect();
+    }
+}
+
+#[clippy::msrv = "1.70.0"]
+fn msrv_too_low() {
+    let x = [1, 2];
+    let x = (x[0], x[1]);
+    let x = [x.0, x.1];
+    let x = &[1, 2];
+    let x = (x[0], x[1]);
+}
+
+#[clippy::msrv = "1.71.0"]
+fn msrv_juust_right() {
+    let x = [1, 2];
+    let x = (x[0], x[1]);
+    let x = [x.0, x.1];
+    let x = &[1, 2];
+    let x = (x[0], x[1]);
+}