Add regression test

tests/src/boxed_field.proto

@@ -0,0 +1,10 @@
+syntax = "proto3";
+
+package boxed_field;
+
+message Foo {
+  Bar bar = 1;
+}
+
+message Bar {
+}

tests/src/build.rs

@@ -171,6 +171,11 @@ fn main() {
         .compile_protos(&[src.join("type_names.proto")], includes)
         .unwrap();
 
+    prost_build::Config::new()
+        .boxed("Foo.bar")
+        .compile_protos(&[src.join("boxed_field.proto")], includes)
+        .unwrap();
+
     // Check that attempting to compile a .proto without a package declaration does not result in an error.
     config
         .compile_protos(&[src.join("no_package.proto")], includes)

tests/src/lib.rs

@@ -140,6 +140,10 @@ pub mod invalid {
     }
 }
 
+pub mod boxed_field {
+    include!(concat!(env!("OUT_DIR"), "/boxed_field.rs"));
+}
+
 pub mod default_string_escape {
     include!(concat!(env!("OUT_DIR"), "/default_string_escape.rs"));
 }