Handle invalid field name

2 files changed, 23 insertions, 2 deletions

diff --git a/src/main/java/org/shedlang/compiler/types/NamespaceTypeInfo.java b/src/main/java/org/shedlang/compiler/types/NamespaceTypeInfo.java
index 7540714b..3c5fbc0b 100644
--- a/src/main/java/org/shedlang/compiler/types/NamespaceTypeInfo.java
+++ b/src/main/java/org/shedlang/compiler/types/NamespaceTypeInfo.java
@@ -8,7 +8,12 @@ public record NamespaceTypeInfo(POrderedMap<String, Type> fields) {
     }
 
     public int fieldIndex(String fieldName) {
-        // TODO: handle missing field
-        return fields.keys().indexOf(fieldName);
+        var fieldIndex = fields.keys().indexOf(fieldName);
+
+        if (fieldIndex == -1) {
+            throw new NoSuchFieldInternalError(fieldName);
+        } else {
+            return fieldIndex;
+        }
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/types/NoSuchFieldInternalError.java b/src/main/java/org/shedlang/compiler/types/NoSuchFieldInternalError.java
new file mode 100644
index 00000000..a465e5b0
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/types/NoSuchFieldInternalError.java
@@ -0,0 +1,16 @@
+package org.shedlang.compiler.types;
+
+import org.shedlang.compiler.errors.InternalCompilerError;
+
+public class NoSuchFieldInternalError extends InternalCompilerError {
+    private final String fieldName;
+
+    public NoSuchFieldInternalError(String fieldName) {
+        super("No such field: " + fieldName);
+        this.fieldName = fieldName;
+    }
+
+    public String fieldName() {
+        return fieldName;
+    }
+}