fix: Ensure the second stack overflow issue errors

Since this test has nested binary expressions it does not overflow the stack or hit the depth checking path in the parser so we also needed the second check.

libflux/flux-core/src/ast/check/mod.rs

@@ -11,15 +11,26 @@ use crate::{
 /// Inspects an AST node and returns a list of found AST errors plus
 /// any errors existed before `ast.check()` is performed.
 pub fn check(node: walk::Node) -> Result<(), Errors<Error>> {
+    const MAX_DEPTH: u32 = 180;
+
     #[derive(Default)]
     struct Check {
+        depth: u32,
         errors: Errors<Error>,
     }
 
     impl<'a> walk::Visitor<'a> for Check {
         fn visit(&mut self, n: walk::Node<'a>) -> bool {
+            self.depth += 1;
+
             let errors = &mut self.errors;
 
+            if self.depth > MAX_DEPTH {
+                errors.push(located(n.base().location.clone(), ErrorKind::NestedToDeep));
+
+                return false;
+            }
+
             // collect any errors we found prior to ast.check().
             for err in n.base().errors.iter() {
                 let err = if err == "Program is nested too deep" {
@@ -87,6 +98,10 @@ pub fn check(node: walk::Node) -> Result<(), Errors<Error>> {
 
             true
         }
+
+        fn done(&mut self, _: walk::Node<'a>) {
+            self.depth -= 1;
+        }
     }
 
     let mut check = Check::default();

libflux/flux-core/src/parser/tests/errors.rs

@@ -938,12 +938,18 @@ builtin y : int
 fn dont_stack_overflow() {
     let mut p = Parser::new(include_str!("stack_overflow.flux"));
     let parsed = p.parse_file("".to_string());
-    assert!(&ast::check::check(ast::walk::Node::File(&parsed)).is_err());
+    assert!(&ast::check::check(ast::walk::Node::File(&parsed))
+        .unwrap_err()
+        .iter()
+        .any(|err| err.error.is_fatal()));
 }
 
 #[test]
 fn dont_stack_overflow_2() {
     let mut p = Parser::new(include_str!("stack_overflow_2.flux"));
     let parsed = p.parse_file("".to_string());
-    assert!(&ast::check::check(ast::walk::Node::File(&parsed)).is_err());
+    assert!(&ast::check::check(ast::walk::Node::File(&parsed))
+        .unwrap_err()
+        .iter()
+        .any(|err| err.error.is_fatal()));
 }