Turns out the issue was the trailing space on the parameters.

src/renderer/walking.rs

@@ -0,0 +1,53 @@
+use crate::renderer::context_element::ContextElement;
+use crate::renderer::WalkError;
+
+enum WalkResult<'a> {
+    NoWalk,
+    PartialWalk,
+    FullyWalked(&'a dyn ContextElement),
+}
+
+fn walk_path_from_single_level<'a>(
+    context: &'a dyn ContextElement,
+    path: &Vec<&str>,
+) -> WalkResult<'a> {
+    if path.is_empty() {
+        return WalkResult::FullyWalked(context);
+    }
+
+    let mut walk_failure = WalkResult::NoWalk;
+    let mut output = context;
+    for elem in path.iter() {
+        let new_val = output.walk(elem);
+        match output.walk(elem) {
+            Err(WalkError::CantWalk { .. }) => {
+                return walk_failure;
+            }
+            Ok(new_val) => {
+                walk_failure = WalkResult::PartialWalk;
+                output = new_val;
+            }
+        }
+    }
+
+    WalkResult::FullyWalked(output)
+}
+
+pub fn walk_path<'a>(
+    breadcrumbs: &Vec<&'a dyn ContextElement>,
+    path: &'a Vec<&str>,
+) -> Result<&'a dyn ContextElement, WalkError> {
+    for context in breadcrumbs.iter().rev() {
+        match walk_path_from_single_level(*context, path) {
+            // If no walking was done at all, keep looping
+            WalkResult::NoWalk => {}
+            // If we partially walked then stop trying to find
+            // anything
+            WalkResult::PartialWalk => {
+                return Err(WalkError::CantWalk);
+            }
+            WalkResult::FullyWalked(new_context) => return Ok(new_context),
+        }
+    }
+    Err(WalkError::CantWalk)
+}