Rust&C++: Fix Return value of complex expression

We were using the has_value of the previous expression of a sequence of
expression, instead of using the last expression type to know if there
is a value.

Fixes #4070

internal/compiler/passes/remove_return.rs

@@ -158,7 +158,7 @@ fn process_codeblock(
                     value,
                     stmts,
                     has_return_value,
-                    has_value,
+                    !matches!(ty, Type::Void | Type::Invalid),
                 );
             }
         }