Auto merge of #11255 - blyxyas:fix-perf-sus_xor_used_as_pow, r=xFrednet

Fix `suspicious_xor_used_as_pow.rs` performance

The original `suspicious_xor_used_as_pow` lint had poor performance, so I fixed that + a little refactor so that module is readable.

**107 millis. -> 106 millis.** Using `SPEEDTEST` on Rust's VMs

fix #11060
changelog: [`suspicious_xor_used_as_pow`]: Improve performance by 0.934%

Author: bors

clippy_lints/src/suspicious_xor_used_as_pow.rs

@@ -1,5 +1,7 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::numeric_literal::NumericLiteral;
-use clippy_utils::source::snippet_with_context;
+use clippy_utils::source::snippet;
+use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
@@ -28,27 +30,29 @@ declare_lint_pass!(ConfusingXorAndPow => [SUSPICIOUS_XOR_USED_AS_POW]);
 
 impl LateLintPass<'_> for ConfusingXorAndPow {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        if !in_external_macro(cx.sess(), expr.span) &&
-        	let ExprKind::Binary(op, left, right) = &expr.kind &&
-            op.node == BinOpKind::BitXor &&
-            left.span.ctxt() == right.span.ctxt() &&
-            let ExprKind::Lit(lit_left) = &left.kind &&
-            let ExprKind::Lit(lit_right) = &right.kind &&
-            let snip_left = snippet_with_context(cx, lit_left.span, lit_left.span.ctxt(), "..", &mut Applicability::MaybeIncorrect) &&
-            let snip_right = snippet_with_context(cx, lit_right.span, lit_right.span.ctxt(), "..", &mut Applicability::MaybeIncorrect) &&
-            let Some(left_val) = NumericLiteral::from_lit_kind(&snip_left.0, &lit_left.node) &&
-            let Some(right_val) = NumericLiteral::from_lit_kind(&snip_right.0, &lit_right.node) &&
-			left_val.is_decimal() &&
-			right_val.is_decimal() {
-					clippy_utils::diagnostics::span_lint_and_sugg(
-					        cx,
-					        SUSPICIOUS_XOR_USED_AS_POW,
-					        expr.span,
-					        "`^` is not the exponentiation operator",
-					        "did you mean to write",
-					        format!("{}.pow({})", left_val.format(), right_val.format()),
-					        Applicability::MaybeIncorrect,
-					    );
+        if !in_external_macro(cx.sess(), expr.span)
+            && let ExprKind::Binary(op, left, right) = &expr.kind
+            && op.node == BinOpKind::BitXor
+            && left.span.ctxt() == right.span.ctxt()
+            && let ExprKind::Lit(lit_left) = &left.kind
+            && let ExprKind::Lit(lit_right) = &right.kind
+            && matches!(lit_right.node, LitKind::Int(..) | LitKind::Float(..))
+            && matches!(lit_left.node, LitKind::Int(..) | LitKind::Float(..))
+            && NumericLiteral::from_lit_kind(&snippet(cx, lit_right.span, ".."), &lit_right.node).is_some_and(|x| x.is_decimal())
+            {
+                span_lint_and_sugg(
+                    cx,
+                    SUSPICIOUS_XOR_USED_AS_POW,
+                    expr.span,
+                    "`^` is not the exponentiation operator",
+                    "did you mean to write",
+                    format!(
+                        "{}.pow({})",
+                        lit_left.node,
+                        lit_right.node
+                    ),
+                    Applicability::MaybeIncorrect,
+                );
 		}
     }
 }

tests/ui/suspicious_xor_used_as_pow.stderr

@@ -10,31 +10,31 @@ error: `^` is not the exponentiation operator
   --> $DIR/suspicious_xor_used_as_pow.rs:20:13
    |
 LL |     let _ = 2i32 ^ 9i32;
-   |             ^^^^^^^^^^^ help: did you mean to write: `2_i32.pow(9_i32)`
+   |             ^^^^^^^^^^^ help: did you mean to write: `2i32.pow(9i32)`
 
 error: `^` is not the exponentiation operator
   --> $DIR/suspicious_xor_used_as_pow.rs:21:13
    |
 LL |     let _ = 2i32 ^ 2i32;
-   |             ^^^^^^^^^^^ help: did you mean to write: `2_i32.pow(2_i32)`
+   |             ^^^^^^^^^^^ help: did you mean to write: `2i32.pow(2i32)`
 
 error: `^` is not the exponentiation operator
   --> $DIR/suspicious_xor_used_as_pow.rs:22:13
    |
 LL |     let _ = 50i32 ^ 3i32;
-   |             ^^^^^^^^^^^^ help: did you mean to write: `50_i32.pow(3_i32)`
+   |             ^^^^^^^^^^^^ help: did you mean to write: `50i32.pow(3i32)`
 
 error: `^` is not the exponentiation operator
   --> $DIR/suspicious_xor_used_as_pow.rs:23:13
    |
 LL |     let _ = 5i32 ^ 8i32;
-   |             ^^^^^^^^^^^ help: did you mean to write: `5_i32.pow(8_i32)`
+   |             ^^^^^^^^^^^ help: did you mean to write: `5i32.pow(8i32)`
 
 error: `^` is not the exponentiation operator
   --> $DIR/suspicious_xor_used_as_pow.rs:24:13
    |
 LL |     let _ = 2i32 ^ 32i32;
-   |             ^^^^^^^^^^^^ help: did you mean to write: `2_i32.pow(32_i32)`
+   |             ^^^^^^^^^^^^ help: did you mean to write: `2i32.pow(32i32)`
 
 error: `^` is not the exponentiation operator
   --> $DIR/suspicious_xor_used_as_pow.rs:13:9