transpile: Make WithStmts::prepend_stmts and add_stmt into builder methods

Author: Rua

c2rust-transpile/src/translator/mod.rs

@@ -3254,7 +3254,7 @@ impl<'c> Translation<'c> {
 
                 if is_explicit {
                     let stmts = self.compute_variable_array_sizes(ctx, ty.ctype)?;
-                    val.prepend_stmts(stmts);
+                    val = val.prepend_stmts(stmts);
                 }
 
                 // Shuffle Vector "function" builtins will add a cast to the output of the

c2rust-transpile/src/with_stmts.rs

@@ -136,13 +136,15 @@ impl<T> WithStmts<T> {
         self.is_unsafe
     }
 
-    pub fn add_stmt(&mut self, stmt: Stmt) {
+    pub fn add_stmt(mut self, stmt: Stmt) -> Self {
         self.stmts.push(stmt);
+        self
     }
 
-    pub fn prepend_stmts(&mut self, mut stmts: Vec<Stmt>) {
+    pub fn prepend_stmts(mut self, mut stmts: Vec<Stmt>) -> Self {
         stmts.append(&mut self.stmts);
         self.stmts = stmts;
+        self
     }
 
     pub fn is_pure(&self) -> bool {