refactor(parser): Ensure action and are are in-sync

src/builder/action.rs

@@ -7,3 +7,14 @@ pub(crate) enum ArgAction {
     Help,
     Version,
 }
+
+impl ArgAction {
+    pub(crate) fn takes_value(&self) -> bool {
+        match self {
+            Self::StoreValue => true,
+            Self::IncOccurrence => false,
+            Self::Help => false,
+            Self::Version => false,
+        }
+    }
+}

src/builder/debug_asserts.rs

@@ -642,6 +642,14 @@ fn assert_arg(arg: &Arg) {
         arg.name,
     );
 
+    assert_eq!(
+        arg.get_action().takes_value(),
+        arg.is_takes_value_set(),
+        "Argument `{}`'s selected action {:?} contradicts `takes_value`",
+        arg.name,
+        arg.get_action()
+    );
+
     if arg.get_value_hint() != ValueHint::Unknown {
         assert!(
             arg.is_takes_value_set(),