diff --git a/src/build/app.rs b/src/build/app.rs
index fd5474f1..77c87ebd 100644
--- a/src/build/app.rs
+++ b/src/build/app.rs
@@ -16,7 +16,6 @@ use yaml_rust::Yaml;
 
 // Internal
 use crate::build::app_settings::{AppFlags, AppSettings};
-use crate::build::debug_asserts::assert_app;
 use crate::build::{arg::ArgProvider, Arg, ArgGroup, ArgPredicate};
 use crate::error::ErrorKind;
 use crate::error::Result as ClapResult;
@@ -26,6 +25,9 @@ use crate::parse::{ArgMatcher, ArgMatches, Input, Parser};
 use crate::util::{color::ColorChoice, Id, Key};
 use crate::{Error, INTERNAL_ERROR_MSG};
 
+#[cfg(debug_assertions)]
+use crate::build::debug_asserts::assert_app;
+
 /// Build a command-line interface.
 ///
 /// This includes defining arguments, subcommands, parser behavior, and help output.
diff --git a/src/build/arg/mod.rs b/src/build/arg.rs
similarity index 99%
rename from src/build/arg/mod.rs
rename to src/build/arg.rs
index b3433213..fd0f81a6 100644
--- a/src/build/arg/mod.rs
+++ b/src/build/arg.rs
@@ -1,15 +1,3 @@
-mod arg_predicate;
-mod possible_value;
-mod settings;
-#[cfg(test)]
-mod tests;
-mod value_hint;
-
-pub use self::possible_value::PossibleValue;
-pub use self::settings::{ArgFlags, ArgSettings};
-pub use self::value_hint::ValueHint;
-pub(crate) use arg_predicate::ArgPredicate;
-
 // Std
 use std::{
     borrow::Cow,
@@ -27,17 +15,16 @@ use std::{env, ffi::OsString};
 use yaml_rust::Yaml;
 
 // Internal
-use crate::{
-    build::usage_parser::UsageParser,
-    util::{Id, Key},
-    INTERNAL_ERROR_MSG,
-};
+use crate::build::usage_parser::UsageParser;
+use crate::build::ArgPredicate;
+use crate::util::{Id, Key};
+use crate::PossibleValue;
+use crate::ValueHint;
+use crate::INTERNAL_ERROR_MSG;
+use crate::{ArgFlags, ArgSettings};
 
 #[cfg(feature = "regex")]
-mod regex;
-
-#[cfg(feature = "regex")]
-pub use self::regex::RegexRef;
+use crate::build::RegexRef;
 
 /// The abstract representation of a command line argument. Used to set all the options and
 /// relationships that define a valid argument for the program.
diff --git a/src/build/arg/arg_predicate.rs b/src/build/arg_predicate.rs
similarity index 100%
rename from src/build/arg/arg_predicate.rs
rename to src/build/arg_predicate.rs
diff --git a/src/build/arg/settings.rs b/src/build/arg_settings.rs
similarity index 100%
rename from src/build/arg/settings.rs
rename to src/build/arg_settings.rs
diff --git a/src/build/arg/tests.rs b/src/build/arg_tests.rs
similarity index 100%
rename from src/build/arg/tests.rs
rename to src/build/arg_tests.rs
diff --git a/src/build/mod.rs b/src/build/mod.rs
index 2c1dd0fe..06ccb7a8 100644
--- a/src/build/mod.rs
+++ b/src/build/mod.rs
@@ -6,16 +6,31 @@ pub mod arg;
 
 mod app_settings;
 mod arg_group;
+mod arg_predicate;
+mod arg_settings;
+mod possible_value;
 mod usage_parser;
+mod value_hint;
+
+#[cfg(feature = "regex")]
+mod regex;
 
 #[cfg(debug_assertions)]
 mod debug_asserts;
 
 #[cfg(test)]
 mod app_tests;
+#[cfg(test)]
+mod arg_tests;
 
-pub use self::app::App;
-pub use self::app_settings::{AppFlags, AppSettings};
-pub use self::arg::{Arg, ArgFlags, ArgSettings, PossibleValue, ValueHint};
-pub use self::arg_group::ArgGroup;
-pub(crate) use arg::ArgPredicate;
+pub use app::App;
+pub use app_settings::{AppFlags, AppSettings};
+pub use arg::Arg;
+pub use arg_group::ArgGroup;
+pub(crate) use arg_predicate::ArgPredicate;
+pub use arg_settings::{ArgFlags, ArgSettings};
+pub use possible_value::PossibleValue;
+pub use value_hint::ValueHint;
+
+#[cfg(feature = "regex")]
+pub use self::regex::RegexRef;
diff --git a/src/build/arg/possible_value.rs b/src/build/possible_value.rs
similarity index 100%
rename from src/build/arg/possible_value.rs
rename to src/build/possible_value.rs
diff --git a/src/build/arg/regex.rs b/src/build/regex.rs
similarity index 100%
rename from src/build/arg/regex.rs
rename to src/build/regex.rs
diff --git a/src/build/arg/value_hint.rs b/src/build/value_hint.rs
similarity index 100%
rename from src/build/arg/value_hint.rs
rename to src/build/value_hint.rs
diff --git a/src/lib.rs b/src/lib.rs
index 792614fd..9a48ae86 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -65,7 +65,7 @@ mod macros;
 mod derive;
 
 #[cfg(feature = "regex")]
-pub use crate::build::arg::RegexRef;
+pub use crate::build::RegexRef;
 
 pub mod error;
 
diff --git a/src/parse/validator.rs b/src/parse/validator.rs
index 4a23c5e8..c2694ba4 100644
--- a/src/parse/validator.rs
+++ b/src/parse/validator.rs
@@ -1,5 +1,5 @@
 // Internal
-use crate::build::{arg::PossibleValue, App, AppSettings as AS, Arg, ArgPredicate};
+use crate::build::{App, AppSettings as AS, Arg, ArgPredicate, PossibleValue};
 use crate::error::{Error, Result as ClapResult};
 use crate::output::Usage;
 use crate::parse::{ArgMatcher, MatchedArg, ParseState, Parser};