fix name evaluation bugs (#1132)

Fixed:
1. Type suffix should be ignored when looking up name
2. If name isn't defined, should return Empty

Author: Andrin Meier

Rubberduck.Parsing/Preprocessing/SymbolTable.cs

@@ -16,6 +16,11 @@ public void Add(string name, object value)
             _table[name] = value;
         }
 
+        public bool HasSymbol(string name)
+        {
+            return _table.ContainsKey(name);            
+        }
+
         public object Get(string name)
         {
             if (_table.ContainsKey(name))

Rubberduck.Parsing/Preprocessing/VBAExpressionEvaluator.cs

@@ -61,7 +61,14 @@ private object Evaluate(VBAConditionalCompilationParser.CcExpressionContext expr
 
         private object Visit(VBAConditionalCompilationParser.NameContext context)
         {
-            var identifier = context.GetText();
+            var identifier = context.IDENTIFIER().GetText();
+            // Special case, identifier that does not exist is VBAEmpty.
+            // Could add them to the symbol table, but since they are all constants
+            // they never change anyway.
+            if (!_symbolTable.HasSymbol(identifier))
+            {
+                return VBAEmptyValue.Value;
+            }
             return _symbolTable.Get(identifier);
         }
 

Rubberduck.Parsing/Preprocessing/VBAPreprocessorVisitor.cs

@@ -53,8 +53,8 @@ public override object VisitCcBlock([NotNull] VBAConditionalCompilationParser.Cc
         public override object VisitCcConst([NotNull] VBAConditionalCompilationParser.CcConstContext context)
         {
             // 3.4.1: If <cc-var-lhs> is a <TYPED-NAME> with a <type-suffix>, the <type-suffix> is ignored.
-            var name = context.ccVarLhs().GetText();
-            _evaluator.EvaluateConstant(name, context.ccExpression());
+            var identifier = context.ccVarLhs().name().IDENTIFIER().GetText();
+            _evaluator.EvaluateConstant(identifier, context.ccExpression());
             return MarkLineAsDead(context.GetText());
         }
 

RubberduckTests/Preprocessing/VBAPreprocessorVisitorTests.cs

@@ -15,9 +15,15 @@ public void TestName()
             string code = @"
 #Const a = 5
 #Const b = a
+#Const c = doesNotExist
+#Const d& = 1
+#Const e = d%
 ";
             var result = Preprocess(code);
             Assert.AreEqual(result.Item1.Get("b"), result.Item1.Get("a"));
+            Assert.AreEqual(VBAEmptyValue.Value, result.Item1.Get("c"));
+            Assert.AreEqual(1m, result.Item1.Get("d"));
+            Assert.AreEqual(1m, result.Item1.Get("e"));
         }
 
         [TestMethod]