From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../clippy/tests/ui/cast_slice_different_sizes.rs  | 82 ++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 src/tools/clippy/tests/ui/cast_slice_different_sizes.rs

(limited to 'src/tools/clippy/tests/ui/cast_slice_different_sizes.rs')

diff --git a/src/tools/clippy/tests/ui/cast_slice_different_sizes.rs b/src/tools/clippy/tests/ui/cast_slice_different_sizes.rs
new file mode 100644
index 000000000..24d7eb28a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/cast_slice_different_sizes.rs
@@ -0,0 +1,82 @@
+#![allow(clippy::let_unit_value)]
+
+fn main() {
+    let x: [i32; 3] = [1_i32, 2, 3];
+    let r_x = &x;
+    // Check casting through multiple bindings
+    // Because it's separate, it does not check the cast back to something of the same size
+    let a = r_x as *const [i32];
+    let b = a as *const [u8];
+    let c = b as *const [u32];
+
+    // loses data
+    let loss = r_x as *const [i32] as *const [u8];
+
+    // Cast back to same size but different type loses no data, just type conversion
+    // This is weird code but there's no reason for this lint specifically to fire *twice* on it
+    let restore = r_x as *const [i32] as *const [u8] as *const [u32];
+
+    // Check casting through blocks is detected
+    let loss_block_1 = { r_x as *const [i32] } as *const [u8];
+    let loss_block_2 = {
+        let _ = ();
+        r_x as *const [i32]
+    } as *const [u8];
+
+    // Check that resores of the same size are detected through blocks
+    let restore_block_1 = { r_x as *const [i32] } as *const [u8] as *const [u32];
+    let restore_block_2 = { ({ r_x as *const [i32] }) as *const [u8] } as *const [u32];
+    let restore_block_3 = {
+        let _ = ();
+        ({
+            let _ = ();
+            r_x as *const [i32]
+        }) as *const [u8]
+    } as *const [u32];
+
+    // Check that the result of a long chain of casts is detected
+    let long_chain_loss = r_x as *const [i32] as *const [u32] as *const [u16] as *const [i8] as *const [u8];
+    let long_chain_restore =
+        r_x as *const [i32] as *const [u32] as *const [u16] as *const [i8] as *const [u8] as *const [u32];
+}
+
+// foo and foo2 should not fire, they're the same size
+fn foo(x: *mut [u8]) -> *mut [u8] {
+    x as *mut [u8]
+}
+
+fn foo2(x: *mut [u8]) -> *mut [u8] {
+    x as *mut _
+}
+
+// Test that casts as part of function returns work
+fn bar(x: *mut [u16]) -> *mut [u8] {
+    x as *mut [u8]
+}
+
+fn uwu(x: *mut [u16]) -> *mut [u8] {
+    x as *mut _
+}
+
+fn bar2(x: *mut [u16]) -> *mut [u8] {
+    x as _
+}
+
+// constify
+fn bar3(x: *mut [u16]) -> *const [u8] {
+    x as _
+}
+
+// unconstify
+fn bar4(x: *const [u16]) -> *mut [u8] {
+    x as _
+}
+
+// function returns plus blocks
+fn blocks(x: *mut [u16]) -> *mut [u8] {
+    ({ x }) as _
+}
+
+fn more_blocks(x: *mut [u16]) -> *mut [u8] {
+    { ({ x }) as _ }
+}
-- 
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