diff --git a/libflux/flux-core/src/ast/check/mod.rs b/libflux/flux-core/src/ast/check/mod.rs
index bbc5e147f9..a4bbaf65d2 100644
--- a/libflux/flux-core/src/ast/check/mod.rs
+++ b/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();
diff --git a/libflux/flux-core/src/parser/tests/errors.rs b/libflux/flux-core/src/parser/tests/errors.rs
index a21dc229a3..010f145166 100644
--- a/libflux/flux-core/src/parser/tests/errors.rs
+++ b/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()));
 }