move mixed_case_hex_literals to its own module

clippy_lints/src/misc_early/mixed_case_hex_literals.rs

@@ -0,0 +1,29 @@
+use clippy_utils::diagnostics::span_lint;
+use rustc_ast::ast::Lit;
+use rustc_lint::EarlyContext;
+
+use super::MIXED_CASE_HEX_LITERALS;
+
+pub(super) fn check(cx: &EarlyContext<'_>, lit: &Lit, maybe_last_sep_idx: usize, lit_snip: String) {
+    if maybe_last_sep_idx <= 2 {
+        // It's meaningless or causes range error.
+        return;
+    }
+    let mut seen = (false, false);
+    for ch in lit_snip.as_bytes()[2..=maybe_last_sep_idx].iter() {
+        match ch {
+            b'a'..=b'f' => seen.0 = true,
+            b'A'..=b'F' => seen.1 = true,
+            _ => {},
+        }
+        if seen.0 && seen.1 {
+            span_lint(
+                cx,
+                MIXED_CASE_HEX_LITERALS,
+                lit.span,
+                "inconsistent casing in hexadecimal literal",
+            );
+            break;
+        }
+    }
+}

clippy_lints/src/misc_early/mod.rs

@@ -1,5 +1,6 @@
 mod builtin_type_shadow;
 mod double_neg;
+mod mixed_case_hex_literals;
 mod redundant_pattern;
 mod unneeded_field_pattern;
 mod unneeded_wildcard_pattern;
@@ -351,27 +352,7 @@ fn check_lit(cx: &EarlyContext<'_>, lit: &Lit) {
             }
 
             if lit_snip.starts_with("0x") {
-                if maybe_last_sep_idx <= 2 {
+                mixed_case_hex_literals::check(cx, lit, maybe_last_sep_idx, lit_snip)
-                    // It's meaningless or causes range error.
-                    return;
-                }
-                let mut seen = (false, false);
-                for ch in lit_snip.as_bytes()[2..=maybe_last_sep_idx].iter() {
-                    match ch {
-                        b'a'..=b'f' => seen.0 = true,
-                        b'A'..=b'F' => seen.1 = true,
-                        _ => {},
-                    }
-                    if seen.0 && seen.1 {
-                        span_lint(
-                            cx,
-                            MIXED_CASE_HEX_LITERALS,
-                            lit.span,
-                            "inconsistent casing in hexadecimal literal",
-                        );
-                        break;
-                    }
-                }
             } else if lit_snip.starts_with("0b") || lit_snip.starts_with("0o") {
                 /* nothing to do */
             } else if value != 0 && lit_snip.starts_with('0') {