Prevent linting on zero values

Author: cgm616

clippy_lints/src/xor_used_as_pow.rs

@@ -55,7 +55,7 @@ impl LateLintPass<'_> for XorUsedAsPow {
             if let ExprKind::Binary(op, left, right) = &expr.kind;
             if BinOpKind::BitXor == op.node;
             if let ExprKind::Lit(lhs) = &left.kind;
-            if let Some((lhs_val, lhs_type)) = unwrap_dec_int_literal(cx, lhs);
+            if let Some((lhs_val, _)) = unwrap_dec_int_literal(cx, lhs);
             then {
                 match &right.kind {
                     ExprKind::Lit(rhs) => {
@@ -110,10 +110,10 @@ fn unwrap_dec_int_literal(cx: &LateContext<'_>, lit: &Lit) -> Option<(u128, LitI
         if let Some(decoded) = NumericLiteral::from_lit_kind(&snippet, &lit.node);
         if decoded.is_decimal();
         then {
-            return Some((val, val_type));
+            Some((val, val_type))
         }
         else {
-            return None;
+            None
         }
     }
 }
@@ -130,16 +130,11 @@ fn report_with_ident(cx: &LateContext<'_>, lhs: u128, rhs: &QPath<'_>, span: Spa
 }
 
 fn report_with_lit(cx: &LateContext<'_>, lhs: u128, rhs: u128, span: Span) {
-    if rhs > 127 {
+    if rhs > 127 || rhs == 0 {
         return;
     }
     match lhs {
         2 => {
-            if rhs == 0 {
-                report_pow_of_two(cx, format!("1"), span);
-                return;
-            }
-
             let lhs_str = if rhs <= 31 {
                 "1_u32"
             } else if rhs <= 63 {

tests/ui/xor_used_as_pow.rs

@@ -1,4 +1,3 @@
-// run-rustfix
 #![warn(clippy::xor_used_as_pow)]
 #![allow(clippy::identity_op)]
 
@@ -19,16 +18,12 @@ fn main() {
     let _ = 10 ^ 0b0101; // rhs binary
     let _ = 2 ^ 0o1; // rhs octal
     let _ = 10 ^ -18; // negative rhs
+    let _ = 2 ^ 0; // zero rhs
 
     // These should fail
-    let _ = 2 ^ 3;
     let _ = 10 ^ 4;
-    let _ = 2 ^ 32;
-    let _ = 2 ^ 0;
-    let _ = 10 ^ 0;
     {
         let x = 15;
-        let _ = 2 ^ x;
         let _ = 10 ^ x;
     }
 }

tests/ui/xor_used_as_pow.stderr

@@ -1,52 +1,19 @@
-error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
-  --> $DIR/xor_used_as_pow.rs:24:13
-   |
-LL |     let _ = 2 ^ 3;
-   |             ^^^^^ help: use a bitshift or constant instead: `1_u32 << 3`
-   |
-   = note: `-D clippy::xor-used-as-pow` implied by `-D warnings`
-
 error: `^` is not an exponentiation operator but appears to have been used as one
-  --> $DIR/xor_used_as_pow.rs:25:13
+  --> $DIR/xor_used_as_pow.rs:24:13
    |
 LL |     let _ = 10 ^ 4;
    |             ^^^^^^
    |
+   = note: `-D clippy::xor-used-as-pow` implied by `-D warnings`
    = help: did you mean to use .pow()?
 
-error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
-  --> $DIR/xor_used_as_pow.rs:26:13
-   |
-LL |     let _ = 2 ^ 32;
-   |             ^^^^^^ help: use a bitshift or constant instead: `1_u64 << 32`
-
-error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
-  --> $DIR/xor_used_as_pow.rs:27:13
-   |
-LL |     let _ = 2 ^ 0;
-   |             ^^^^^ help: use a bitshift or constant instead: `1`
-
-error: `^` is not an exponentiation operator but appears to have been used as one
-  --> $DIR/xor_used_as_pow.rs:28:13
-   |
-LL |     let _ = 10 ^ 0;
-   |             ^^^^^^
-   |
-   = help: did you mean to use .pow()?
-
-error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
-  --> $DIR/xor_used_as_pow.rs:31:17
-   |
-LL |         let _ = 2 ^ x;
-   |                 ^^^^^ help: use a bitshift or constant instead: `1 << x`
-
 error: `^` is not an exponentiation operator but appears to have been used as one
-  --> $DIR/xor_used_as_pow.rs:32:17
+  --> $DIR/xor_used_as_pow.rs:27:17
    |
 LL |         let _ = 10 ^ x;
    |                 ^^^^^^
    |
    = help: did you mean to use .pow()?
 
-error: aborting due to 7 previous errors
+error: aborting due to 2 previous errors
 

tests/ui/xor_used_as_pow.fixed renamed to tests/ui/xor_used_as_pow_fixable.fixed

@@ -19,16 +19,13 @@ fn main() {
     let _ = 10 ^ 0b0101; // rhs binary
     let _ = 2 ^ 0o1; // rhs octal
     let _ = 10 ^ -18; // negative rhs
+    let _ = 2 ^ 0; // zero rhs
 
     // These should fail
     let _ = 1_u32 << 3;
-    let _ = 10 ^ 4;
     let _ = 1_u64 << 32;
-    let _ = 1;
-    let _ = 10 ^ 0;
     {
         let x = 15;
         let _ = 1 << x;
-        let _ = 10 ^ x;
     }
 }

tests/ui/xor_used_as_pow_fixable.rs

@@ -0,0 +1,31 @@
+// run-rustfix
+#![warn(clippy::xor_used_as_pow)]
+#![allow(clippy::identity_op)]
+
+// Should not be linted
+#[allow(dead_code)]
+enum E {
+    First = 1 ^ 8,
+    Second = 2 ^ 8,
+    Third = 3 ^ 8,
+    Tenth = 10 ^ 8,
+}
+
+fn main() {
+    // These should succeed:
+    let _ = 9 ^ 3; // lhs other than 2 or 10
+    let _ = 0x02 ^ 6; // lhs not decimal
+    let _ = 2 ^ 0x10; // rhs hexadecimal
+    let _ = 10 ^ 0b0101; // rhs binary
+    let _ = 2 ^ 0o1; // rhs octal
+    let _ = 10 ^ -18; // negative rhs
+    let _ = 2 ^ 0; // zero rhs
+
+    // These should fail
+    let _ = 2 ^ 3;
+    let _ = 2 ^ 32;
+    {
+        let x = 15;
+        let _ = 2 ^ x;
+    }
+}

tests/ui/xor_used_as_pow_fixable.stderr

@@ -0,0 +1,22 @@
+error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
+  --> $DIR/xor_used_as_pow_fixable.rs:25:13
+   |
+LL |     let _ = 2 ^ 3;
+   |             ^^^^^ help: use a bitshift or constant instead: `1_u32 << 3`
+   |
+   = note: `-D clippy::xor-used-as-pow` implied by `-D warnings`
+
+error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
+  --> $DIR/xor_used_as_pow_fixable.rs:26:13
+   |
+LL |     let _ = 2 ^ 32;
+   |             ^^^^^^ help: use a bitshift or constant instead: `1_u64 << 32`
+
+error: it appears you are trying to get a power of two, but `^` is not an exponentiation operator
+  --> $DIR/xor_used_as_pow_fixable.rs:29:17
+   |
+LL |         let _ = 2 ^ x;
+   |                 ^^^^^ help: use a bitshift or constant instead: `1 << x`
+
+error: aborting due to 3 previous errors
+