Move wrong_transmute to its own module

Author: magurotuna

clippy_lints/src/transmute/mod.rs

@@ -1,5 +1,6 @@
 mod useless_transmute;
 mod utils;
+mod wrong_transmute;
 
 use utils::*;
 
@@ -350,14 +351,12 @@ impl<'tcx> LateLintPass<'tcx> for Transmute {
                 if triggered {
                     return;
                 }
+                let triggered = wrong_transmute::check(cx, e, from_ty, to_ty);
+                if triggered {
+                    return;
+                }
 
                 match (&from_ty.kind(), &to_ty.kind()) {
-                    (ty::Float(_) | ty::Char, ty::Ref(..) | ty::RawPtr(_)) => span_lint(
-                        cx,
-                        WRONG_TRANSMUTE,
-                        e.span,
-                        &format!("transmute from a `{}` to a pointer", from_ty),
-                    ),
                     (ty::RawPtr(from_ptr), _) if from_ptr.ty == to_ty => span_lint(
                         cx,
                         CROSSPOINTER_TRANSMUTE,

clippy_lints/src/transmute/wrong_transmute.rs

@@ -0,0 +1,23 @@
+use super::WRONG_TRANSMUTE;
+use crate::utils::span_lint;
+use rustc_hir::Expr;
+use rustc_lint::LateContext;
+use rustc_middle::ty;
+use rustc_middle::ty::Ty;
+
+/// Checks for `wrong_transmute` lint.
+/// Returns `true` if it's triggered, otherwise returns `false`.
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>, from_ty: Ty<'tcx>, to_ty: Ty<'tcx>) -> bool {
+    match (&from_ty.kind(), &to_ty.kind()) {
+        (ty::Float(_) | ty::Char, ty::Ref(..) | ty::RawPtr(_)) => {
+            span_lint(
+                cx,
+                WRONG_TRANSMUTE,
+                e.span,
+                &format!("transmute from a `{}` to a pointer", from_ty),
+            );
+            true
+        },
+        _ => false,
+    }
+}