Fix type for externally declared control variable - fixes #609

Author: GrahamTheCoder

CHANGELOG.md

@@ -14,6 +14,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 * Convert bitwise negation [#599](https://github.com/icsharpcode/CodeConverter/issues/599)
 * No longer adds incorrect "base" qualification for virtual method calls [#600](https://github.com/icsharpcode/CodeConverter/issues/600)
 * Don't generate unnecessary properties for WithEvents fields [#572](https://github.com/icsharpcode/CodeConverter/issues/572)
+* Add type conversion where needed for externally declared loop control variable [#609](https://github.com/icsharpcode/CodeConverter/issues/609)
 
 ### C# -> VB
 

CodeConverter/CSharp/MethodBodyExecutableStatementVisitor.cs

@@ -500,12 +500,13 @@ private async Task<StatementSyntax[]> ConvertStatementsAsync(SyntaxList<VBSyntax
         public override async Task<SyntaxList<StatementSyntax>> VisitForBlock(VBSyntax.ForBlockSyntax node)
         {
             var stmt = node.ForStatement;
-            var startValue = await stmt.FromValue.AcceptAsync<ExpressionSyntax>(_expressionVisitor);
             VariableDeclarationSyntax declaration = null;
             ExpressionSyntax id;
-            var controlVarOp = _semanticModel.GetOperation(stmt.ControlVariable) as IVariableDeclaratorOperation;
-            var controlVarSymbol = controlVarOp?.Symbol;
-            var controlVarType = controlVarSymbol?.Type;
+            var controlVarSymbol  = _semanticModel.GetSymbolInfo(stmt.ControlVariable).Symbol;
+            var controlVarType = controlVarSymbol?.GetSymbolType();
+            var startValue = await stmt.FromValue.AcceptAsync<ExpressionSyntax>(_expressionVisitor);
+            startValue = CommonConversions.TypeConversionAnalyzer.AddExplicitConversion(stmt.FromValue, startValue?.SkipIntoParens(), forceTargetType: controlVarType);
+            
             var initializers = new List<ExpressionSyntax>();
             if (stmt.ControlVariable is VBSyntax.VariableDeclaratorSyntax) {
                 var v = (VBSyntax.VariableDeclaratorSyntax)stmt.ControlVariable;

Tests/CSharp/StatementTests/LoopStatementTests.cs

@@ -382,6 +382,41 @@ public static void Main(string[] args)
 }");
         }
 
+        [Fact]
+        public async Task Int16ForLoopAsync()
+        {
+            await TestConversionVisualBasicToCSharpAsync(@"    Sub DummyMethod()
+        Dim someArray = New Integer() { 1, 2, 3}
+        For index As Int16 = 0 To someArray.Length - 1
+            Console.WriteLine(index)
+        Next
+    End Sub", @"public void DummyMethod()
+{
+    var someArray = new int[] { 1, 2, 3 };
+    for (short index = 0, loopTo = Conversions.ToShort(someArray.Length - 1); index <= loopTo; index++)
+        Console.WriteLine(index);
+}");
+        }
+
+        [Fact]
+        public async Task ExternallyDeclaredLoopVariableAsync()
+        {
+            await TestConversionVisualBasicToCSharpAsync(@"Sub Main()
+    Dim foo As Single = 3.5
+    Dim index As Integer
+    For index = Int(foo) To Int(foo * 3)
+        Console.WriteLine(index)
+    Next
+End Sub", @"public void Main()
+{
+    float foo = 3.5F;
+    int index;
+    var loopTo = Conversions.ToInteger(Conversion.Int(foo * 3));
+    for (index = Conversions.ToInteger(Conversion.Int(foo)); index <= loopTo; index++)
+        Console.WriteLine(index);
+}");
+        }
+
         [Fact]
         public async Task ForNonNegativeStepAsync()
         {