5 files changed, 217 insertions, 0 deletions
diff --git a/tests/ui/non_zero_suggestions.fixed b/tests/ui/non_zero_suggestions.fixed
new file mode 100644
index 00000000000..9851063782e
--- /dev/null
+++ b/tests/ui/non_zero_suggestions.fixed
@@ -0,0 +1,65 @@
+#![warn(clippy::non_zero_suggestions)]
+use std::num::{NonZeroI16, NonZeroI8, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize};
+
+fn main() {
+    /// Positive test cases (lint should trigger)
+    // U32 -> U64
+    let x: u64 = 100;
+    let y = NonZeroU32::new(10).unwrap();
+    let r1 = x / NonZeroU64::from(y);
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    let r2 = x % NonZeroU64::from(y);
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    // U16 -> U32
+    let a: u32 = 50;
+    let b = NonZeroU16::new(5).unwrap();
+    let r3 = a / NonZeroU32::from(b);
+    //~^ ERROR: consider using `NonZeroU32::from()` for more efficient and type-safe conversion
+
+    let x = NonZeroU64::from(NonZeroU32::new(5).unwrap());
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    /// Negative test cases (lint should not trigger)
+    // Left hand side expressions should not be triggered
+    let c: u32 = 50;
+    let d = NonZeroU16::new(5).unwrap();
+    let r4 = u32::from(b.get()) / a;
+
+    // Should not trigger for any other operand other than `/` and `%`
+    let r5 = a + u32::from(b.get());
+    let r6 = a - u32::from(b.get());
+
+    // Same size types
+    let e: u32 = 200;
+    let f = NonZeroU32::new(20).unwrap();
+    let r7 = e / f.get();
+
+    // Smaller to larger, but not NonZero
+    let g: u64 = 1000;
+    let h: u32 = 50;
+    let r8 = g / u64::from(h);
+
+    // Using From correctly
+    let k: u64 = 300;
+    let l = NonZeroU32::new(15).unwrap();
+    let r9 = k / NonZeroU64::from(l);
+}
+
+// Additional function to test the lint in a different context
+fn divide_numbers(x: u64, y: NonZeroU32) -> u64 {
+    x / NonZeroU64::from(y)
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+}
+
+struct Calculator {
+    value: u64,
+}
+
+impl Calculator {
+    fn divide(&self, divisor: NonZeroU32) -> u64 {
+        self.value / NonZeroU64::from(divisor)
+        //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+    }
+}
diff --git a/tests/ui/non_zero_suggestions.rs b/tests/ui/non_zero_suggestions.rs
new file mode 100644
index 00000000000..1605c459248
--- /dev/null
+++ b/tests/ui/non_zero_suggestions.rs
@@ -0,0 +1,65 @@
+#![warn(clippy::non_zero_suggestions)]
+use std::num::{NonZeroI16, NonZeroI8, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize};
+
+fn main() {
+    /// Positive test cases (lint should trigger)
+    // U32 -> U64
+    let x: u64 = 100;
+    let y = NonZeroU32::new(10).unwrap();
+    let r1 = x / u64::from(y.get());
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    let r2 = x % u64::from(y.get());
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    // U16 -> U32
+    let a: u32 = 50;
+    let b = NonZeroU16::new(5).unwrap();
+    let r3 = a / u32::from(b.get());
+    //~^ ERROR: consider using `NonZeroU32::from()` for more efficient and type-safe conversion
+
+    let x = u64::from(NonZeroU32::new(5).unwrap().get());
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    /// Negative test cases (lint should not trigger)
+    // Left hand side expressions should not be triggered
+    let c: u32 = 50;
+    let d = NonZeroU16::new(5).unwrap();
+    let r4 = u32::from(b.get()) / a;
+
+    // Should not trigger for any other operand other than `/` and `%`
+    let r5 = a + u32::from(b.get());
+    let r6 = a - u32::from(b.get());
+
+    // Same size types
+    let e: u32 = 200;
+    let f = NonZeroU32::new(20).unwrap();
+    let r7 = e / f.get();
+
+    // Smaller to larger, but not NonZero
+    let g: u64 = 1000;
+    let h: u32 = 50;
+    let r8 = g / u64::from(h);
+
+    // Using From correctly
+    let k: u64 = 300;
+    let l = NonZeroU32::new(15).unwrap();
+    let r9 = k / NonZeroU64::from(l);
+}
+
+// Additional function to test the lint in a different context
+fn divide_numbers(x: u64, y: NonZeroU32) -> u64 {
+    x / u64::from(y.get())
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+}
+
+struct Calculator {
+    value: u64,
+}
+
+impl Calculator {
+    fn divide(&self, divisor: NonZeroU32) -> u64 {
+        self.value / u64::from(divisor.get())
+        //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+    }
+}
diff --git a/tests/ui/non_zero_suggestions.stderr b/tests/ui/non_zero_suggestions.stderr
new file mode 100644
index 00000000000..7a57f7983be
--- /dev/null
+++ b/tests/ui/non_zero_suggestions.stderr
@@ -0,0 +1,41 @@
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions.rs:9:18
+   |
+LL |     let r1 = x / u64::from(y.get());
+   |                  ^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(y)`
+   |
+   = note: `-D clippy::non-zero-suggestions` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::non_zero_suggestions)]`
+
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions.rs:12:18
+   |
+LL |     let r2 = x % u64::from(y.get());
+   |                  ^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(y)`
+
+error: consider using `NonZeroU32::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions.rs:18:18
+   |
+LL |     let r3 = a / u32::from(b.get());
+   |                  ^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU32::from(b)`
+
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions.rs:21:13
+   |
+LL |     let x = u64::from(NonZeroU32::new(5).unwrap().get());
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(NonZeroU32::new(5).unwrap())`
+
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions.rs:52:9
+   |
+LL |     x / u64::from(y.get())
+   |         ^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(y)`
+
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions.rs:62:22
+   |
+LL |         self.value / u64::from(divisor.get())
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(divisor)`
+
+error: aborting due to 6 previous errors
+
diff --git a/tests/ui/non_zero_suggestions_unfixable.rs b/tests/ui/non_zero_suggestions_unfixable.rs
new file mode 100644
index 00000000000..4eb22a8d4c7
--- /dev/null
+++ b/tests/ui/non_zero_suggestions_unfixable.rs
@@ -0,0 +1,23 @@
+#![warn(clippy::non_zero_suggestions)]
+//@no-rustfix
+use std::num::{NonZeroI16, NonZeroI8, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize};
+
+fn main() {
+    let x: u64 = u64::from(NonZeroU32::new(5).unwrap().get());
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+
+    let n = NonZeroU32::new(20).unwrap();
+    let y = u64::from(n.get());
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+    some_fn_that_only_takes_u64(y);
+
+    let m = NonZeroU32::try_from(1).unwrap();
+    let _z: NonZeroU64 = m.into();
+}
+
+fn return_non_zero(x: u64, y: NonZeroU32) -> u64 {
+    u64::from(y.get())
+    //~^ ERROR: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+}
+
+fn some_fn_that_only_takes_u64(_: u64) {}
diff --git a/tests/ui/non_zero_suggestions_unfixable.stderr b/tests/ui/non_zero_suggestions_unfixable.stderr
new file mode 100644
index 00000000000..787179f2a2d
--- /dev/null
+++ b/tests/ui/non_zero_suggestions_unfixable.stderr
@@ -0,0 +1,23 @@
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions_unfixable.rs:6:18
+   |
+LL |     let x: u64 = u64::from(NonZeroU32::new(5).unwrap().get());
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(NonZeroU32::new(5).unwrap())`
+   |
+   = note: `-D clippy::non-zero-suggestions` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::non_zero_suggestions)]`
+
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions_unfixable.rs:10:13
+   |
+LL |     let y = u64::from(n.get());
+   |             ^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(n)`
+
+error: consider using `NonZeroU64::from()` for more efficient and type-safe conversion
+  --> tests/ui/non_zero_suggestions_unfixable.rs:19:5
+   |
+LL |     u64::from(y.get())
+   |     ^^^^^^^^^^^^^^^^^^ help: replace with: `NonZeroU64::from(y)`
+
+error: aborting due to 3 previous errors
+