From 2c8498cd2d2dea218cd5b01667b17352d8f3d786 Mon Sep 17 00:00:00 2001
From: Tim Fennis <tim.fennis@nos.nl>
Date: Fri, 5 Dec 2025 07:25:58 +0100
Subject: [PATCH] Fixed variable name resolution bug

---
 ndc_lib/src/interpreter/environment.rs |  4 ++++
 ndc_lib/src/interpreter/mod.rs         |  2 +-
 ndc_lib/src/interpreter/resolve.rs     | 24 ++++++++++++++----------
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/ndc_lib/src/interpreter/environment.rs b/ndc_lib/src/interpreter/environment.rs
index 4455e4b9..aba7e14f 100644
--- a/ndc_lib/src/interpreter/environment.rs
+++ b/ndc_lib/src/interpreter/environment.rs
@@ -155,6 +155,10 @@ impl Environment {
 
     fn get_copy_from_slot(&self, depth: usize, slot: usize) -> Value {
         if depth == 0 {
+            assert!(
+                self.values.len() > slot,
+                "failed to take item out of slot {slot} because it was empty"
+            );
             self.values[slot].clone()
         } else {
             self.parent
diff --git a/ndc_lib/src/interpreter/mod.rs b/ndc_lib/src/interpreter/mod.rs
index 19d04513..fdb5d5b0 100644
--- a/ndc_lib/src/interpreter/mod.rs
+++ b/ndc_lib/src/interpreter/mod.rs
@@ -72,7 +72,7 @@ impl Interpreter {
         }
 
         // dbg!(&expressions);
-        // dbg!(&lex_data);
+        // dbg!(&self.lexical_data);
 
         let final_value = self.interpret(expressions.into_iter())?;
 
diff --git a/ndc_lib/src/interpreter/resolve.rs b/ndc_lib/src/interpreter/resolve.rs
index c8afe381..c6afad09 100644
--- a/ndc_lib/src/interpreter/resolve.rs
+++ b/ndc_lib/src/interpreter/resolve.rs
@@ -56,8 +56,8 @@ pub fn resolve_pass(
             resolve_pass(expr, lexical_data)?;
         }
         Expression::VariableDeclaration { l_value, value } => {
-            resolve_lvalue_declarative(l_value, lexical_data)?;
             resolve_pass(value, lexical_data)?;
+            resolve_lvalue_declarative(l_value, lexical_data)?;
         }
         Expression::Assignment { l_value, r_value } => {
             resolve_lvalue(l_value, *span, lexical_data)?;
@@ -118,7 +118,7 @@ pub fn resolve_pass(
                 {
                     Some(binding)
                 } else {
-                    Some(lexical_data.create_binding(function_ident))
+                    Some(lexical_data.create_local_binding(function_ident))
                 }
             }
 
@@ -358,9 +358,11 @@ fn resolve_arguments_declarative(
             panic!("expected tuple values to be ident");
         };
 
-        *resolved = Some(lexical_data.create_binding(LexicalIdentifier::Variable {
-            name: (*name).clone(),
-        }));
+        *resolved = Some(
+            lexical_data.create_local_binding(LexicalIdentifier::Variable {
+                name: (*name).clone(),
+            }),
+        );
     }
 }
 fn resolve_lvalue_declarative(
@@ -372,9 +374,11 @@ fn resolve_lvalue_declarative(
             identifier,
             resolved,
         } => {
-            *resolved = Some(lexical_data.create_binding(LexicalIdentifier::Variable {
-                name: (*identifier).clone(),
-            }));
+            *resolved = Some(
+                lexical_data.create_local_binding(LexicalIdentifier::Variable {
+                    name: (*identifier).clone(),
+                }),
+            );
         }
         Lvalue::Index { index, value } => {
             resolve_pass(index, lexical_data)?;
@@ -484,7 +488,7 @@ impl LexicalData {
         }
     }
 
-    fn create_binding(&mut self, ident: LexicalIdentifier) -> ResolvedVar {
+    fn create_local_binding(&mut self, ident: LexicalIdentifier) -> ResolvedVar {
         ResolvedVar::Captured {
             slot: self.scopes[self.current_scope_idx].allocate(ident),
             depth: 0,
@@ -543,7 +547,7 @@ impl LexicalScope {
 
     fn allocate(&mut self, name: LexicalIdentifier) -> usize {
         self.identifiers.push(name);
-        // Slot is just th elength of the list
+        // Slot is just the length of the list
         self.identifiers.len() - 1
     }
 }