fix(acir_gen): A slice might be a nested Array, not a flattened DynamicArray

compiler/noirc_evaluator/src/acir/mod.rs

@@ -1422,6 +1422,7 @@ impl<'a> Context<'a> {
                 let new_slice_length = self.acir_context.sub_var(slice_length, one)?;
 
                 let slice = self.convert_value(slice_contents, dfg);
+                let is_dynamic = matches!(slice, AcirValue::DynamicArray(_));
 
                 let mut new_slice = self.read_array(slice)?;
 
@@ -1443,6 +1444,11 @@ impl<'a> Context<'a> {
 
                 // It is expected that the `popped_elements_size` is the flattened size of the elements,
                 // as the input slice should be a dynamic array which is represented by flat memory.
+                // However in some cases the input slice is an Array with a nested structure,
+                // in which case we only need to pop the items that represent a single entry.
+                let popped_elements_size =
+                    if is_dynamic { popped_elements_size } else { element_size };
+
                 new_slice = new_slice.slice(popped_elements_size..);
 
                 popped_elements.push(AcirValue::Var(new_slice_length, AcirType::field()));

test_programs/execution_success/regression_9593/Nargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "regression_9593"
+type = "bin"
+authors = [""]
+
+[dependencies]

test_programs/execution_success/regression_9593/Prover.toml

@@ -0,0 +1,2 @@
+a = true
+return = "Cc"

test_programs/execution_success/regression_9593/src/main.nr

@@ -0,0 +1,11 @@
+fn main(a: bool) -> pub str<2> {
+    let (_, d) = {
+        let b: [str<2>] = if a {
+            &["Aa", "Bb", "Cc"]
+        } else {
+            &["Dd", "Ee"]
+        };
+        b.pop_front()
+    };
+    d[1]
+}