Suggest using deref in patterns

Fixes #132784

compiler/rustc_hir/src/hir.rs

@@ -2020,6 +2020,22 @@ pub fn is_range_literal(expr: &Expr<'_>) -> bool {
     }
 }
 
+/// Checks if the specified expression needs parentheses for prefix
+/// or postfix suggestions to be valid.
+/// For example, `a + b` requires parentheses to suggest `&(a + b)`,
+/// but just `a` does not.
+/// Similarly, `(a + b).c()` also requires parentheses.
+/// This should not be used for other types of suggestions.
+pub fn expr_needs_parens(expr: &Expr<'_>) -> bool {
+    match expr.kind {
+        // parenthesize if needed (Issue #46756)
+        ExprKind::Cast(_, _) | ExprKind::Binary(_, _, _) => true,
+        // parenthesize borrows of range literals (Issue #54505)
+        _ if is_range_literal(expr) => true,
+        _ => false,
+    }
+}
+
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub enum ExprKind<'hir> {
     /// Allow anonymous constants from an inline `const` block