Extract integer conversion into a function

compiler/rustc_lint/src/types/literal.rs

@@ -204,16 +204,13 @@ fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<&'static
     match t.kind() {
         ty::Uint(ty::UintTy::Usize) | ty::Int(ty::IntTy::Isize) => None,
         ty::Uint(_) => Some(Integer::fit_unsigned(val).uint_ty_str()),
-        ty::Int(_) if negative => {
-            if val > i128::MAX as u128 + 1 {
-                None
-            } else {
-                Some(Integer::fit_signed(val.wrapping_neg() as i128).int_ty_str())
-            }
-        }
         ty::Int(int) => {
+            let signed = literal_to_i128(val, negative).map(|v| Integer::fit_signed(v));
+            if negative {
+                signed.map(Integer::int_ty_str)
+            } else {
                 let unsigned = Integer::fit_unsigned(val);
-            Some(if let Ok(signed) = i128::try_from(val).map(Integer::fit_signed) {
+                Some(if let Some(signed) = signed {
                     if Some(unsigned.size().bits()) == int.bit_width() {
                         unsigned.uint_ty_str()
                     } else {
@@ -223,10 +220,19 @@ fn get_type_suggestion(t: Ty<'_>, val: u128, negative: bool) -> Option<&'static
                     unsigned.uint_ty_str()
                 })
             }
+        }
         _ => None,
     }
 }
 
+fn literal_to_i128(val: u128, negative: bool) -> Option<i128> {
+    if negative {
+        (val <= i128::MAX as u128 + 1).then(|| val.wrapping_neg() as i128)
+    } else {
+        val.try_into().ok()
+    }
+}
+
 fn lint_int_literal<'tcx>(
     cx: &LateContext<'tcx>,
     type_limits: &TypeLimits,