...

compiler/TypeChecker.cs

@@ -191,9 +191,22 @@ public class TypeChecker
         if (target.Type is not NubTypeEnum enumType)
             throw BasicError("A match statement can only be used on enum types", target);
 
+        if (!moduleGraph.TryResolveType(enumType.Module, enumType.Name, enumType.Module == currentModule, out var info))
+            throw BasicError($"Type '{enumType}' not found", target);
+
+        if (info is not Module.TypeInfoEnum enumInfo)
+            throw BasicError($"Type '{enumType}' is not an enum", target);
+
+        var uncoveredCases = enumInfo.Variants.Select(x => x.Name).ToList();
+
         var cases = new List<TypedNodeStatementMatch.Case>();
         foreach (var @case in statement.Cases)
         {
+            if (!enumInfo.Variants.Any(x => x.Name == @case.Variant.Ident))
+                throw BasicError($"Enum type'{enumType}' does not have a variant named '{@case.Variant.Ident}'", @case.Variant);
+
+            uncoveredCases.Remove(@case.Variant.Ident);
+
             using (scope.EnterScope())
             {
                 scope.DeclareIdentifier(@case.VariableName.Ident, NubTypeEnumVariant.Get(NubTypeEnum.Get(enumType.Module, enumType.Name), @case.Variant.Ident));
@@ -202,6 +215,9 @@ public class TypeChecker
             }
         }
 
+        if (uncoveredCases.Any())
+            throw BasicError($"Match statement does not cover the following cases: {string.Join(", ",  uncoveredCases)}", statement);
+
         return new TypedNodeStatementMatch(statement.Tokens, target, cases);
     }
 
@@ -791,7 +807,7 @@ public class TypedNodeStatementMatch(List<Token> tokens, TypedNodeExpression tar
 
     public class Case(List<Token> tokens, TokenIdent type, TokenIdent variableName, TypedNodeStatement body) : Node(tokens)
     {
-        public TokenIdent Type { get; } = type;
+        public TokenIdent Variant { get; } = type;
         public TokenIdent VariableName { get; } = variableName;
         public TypedNodeStatement Body { get; } = body;
     }