Select case for a mixture of strings and characters converts correctly - fixes #1061

Author: GrahamTheCoder

CHANGELOG.md

@@ -12,6 +12,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 * Remove square brackets from identifiers [#1043](https://github.com/icsharpcode/CodeConverter/issues/1043)
 * Conversion of parenthesized ref arguments no longer assigns back [#1046](https://github.com/icsharpcode/CodeConverter/issues/1046)
+* Conversion of explicit interface implementations now converts optional parameters [#1062](https://github.com/icsharpcode/CodeConverter/issues/1062)
+* Constant chars are converted to constant strings where needed
+* Select case for a mixture of strings and characters converts correctly [#1062](https://github.com/icsharpcode/CodeConverter/issues/1062)
+
 
 ### C# -> VB
 

CodeConverter/CSharp/MethodBodyExecutableStatementVisitor.cs

@@ -770,7 +770,9 @@ public override async Task<SyntaxList<StatementSyntax>> VisitSelectBlock(VBSynta
 
                     // CSharp requires an explicit cast from the base type (e.g. int) in most cases switching on an enum
                     var isBooleanCase = caseTypeInfo.Type?.SpecialType == SpecialType.System_Boolean;
-                    var csExpressionToUse = IsEnumOrNullableEnum(switchExprTypeInfo.ConvertedType) ^ IsEnumOrNullableEnum(caseTypeInfo.Type) && !isBooleanCase ? correctTypeExpressionSyntax.Expr : originalExpressionSyntax;
+                    bool enumRelated = IsEnumOrNullableEnum(switchExprTypeInfo.ConvertedType) || IsEnumOrNullableEnum(caseTypeInfo.Type);
+                    bool convertingEnum = IsEnumOrNullableEnum(switchExprTypeInfo.ConvertedType) ^ IsEnumOrNullableEnum(caseTypeInfo.Type);
+                    var csExpressionToUse = !isBooleanCase && (convertingEnum || !enumRelated && correctTypeExpressionSyntax.IsConst) ? correctTypeExpressionSyntax.Expr : originalExpressionSyntax;
 
                     var caseSwitchLabelSyntax = !wrapForStringComparison && correctTypeExpressionSyntax.IsConst && notAlreadyUsed
                         ? (SwitchLabelSyntax)SyntaxFactory.CaseSwitchLabel(csExpressionToUse)
@@ -783,14 +785,19 @@ public override async Task<SyntaxList<StatementSyntax>> VisitSelectBlock(VBSynta
                     var varName = CommonConversions.CsEscapedIdentifier(GetUniqueVariableNameInScope(node, "case"));
                     ExpressionSyntax csLeft = ValidSyntaxFactory.IdentifierName(varName);
                     var operatorKind = VBasic.VisualBasicExtensions.Kind(relational);
-                    var relationalValue = await relational.Value.AcceptAsync<ExpressionSyntax>(_expressionVisitor);
-                    var binaryExp = SyntaxFactory.BinaryExpression(operatorKind.ConvertToken(), csLeft, relationalValue);
+                    var csRelationalValue = await relational.Value.AcceptAsync<ExpressionSyntax>(_expressionVisitor);
+                    csRelationalValue = CommonConversions.TypeConversionAnalyzer.AddExplicitConversion(relational.Value, csRelationalValue);
+                    var binaryExp = SyntaxFactory.BinaryExpression(operatorKind.ConvertToken(), csLeft, csRelationalValue);
                     labels.Add(VarWhen(varName, binaryExp));
                 } else if (c is VBSyntax.RangeCaseClauseSyntax range) {
                     var varName = CommonConversions.CsEscapedIdentifier(GetUniqueVariableNameInScope(node, "case"));
                     ExpressionSyntax csLeft = ValidSyntaxFactory.IdentifierName(varName);
-                    var lowerBoundCheck = SyntaxFactory.BinaryExpression(SyntaxKind.LessThanOrEqualExpression, await range.LowerBound.AcceptAsync<ExpressionSyntax>(_expressionVisitor), csLeft);
-                    var upperBoundCheck = SyntaxFactory.BinaryExpression(SyntaxKind.LessThanOrEqualExpression, csLeft, await range.UpperBound.AcceptAsync<ExpressionSyntax>(_expressionVisitor));
+                    var lowerBound = await range.LowerBound.AcceptAsync<ExpressionSyntax>(_expressionVisitor);
+                    lowerBound = CommonConversions.TypeConversionAnalyzer.AddExplicitConversion(range.LowerBound, lowerBound);
+                    var lowerBoundCheck = SyntaxFactory.BinaryExpression(SyntaxKind.LessThanOrEqualExpression, lowerBound, csLeft);
+                    var upperBound = await range.UpperBound.AcceptAsync<ExpressionSyntax>(_expressionVisitor);
+                    upperBound = CommonConversions.TypeConversionAnalyzer.AddExplicitConversion(range.UpperBound, upperBound);
+                    var upperBoundCheck = SyntaxFactory.BinaryExpression(SyntaxKind.LessThanOrEqualExpression, csLeft, upperBound);
                     var withinBounds = SyntaxFactory.BinaryExpression(SyntaxKind.LogicalAndExpression, lowerBoundCheck, upperBoundCheck);
                     labels.Add(VarWhen(varName, withinBounds));
                 } else {

Tests/CSharp/TypeCastTests.cs

@@ -1360,6 +1360,42 @@ private string[] QuoteSplit(string text)
 }");
     }
 
+
+    [Fact]
+    public async Task TestSelectCaseComparesCharsAndStringsAsync()
+    {
+        await TestConversionVisualBasicToCSharpAsync(
+            @"
+Class CharTestClass
+    Private Sub Q()
+        Select Case ""a""
+            Case ""x""c To ""y""c
+            Case ""b""c
+        End Select
+    End Sub
+End Class", @"
+internal partial class CharTestClass
+{
+    private void Q()
+    {
+        switch (""a"")
+        {
+            case var @case when ""x"" <= @case && @case <= ""y"":
+                {
+                    break;
+                }
+
+            case ""b"":
+                {
+                    break;
+                }
+        }
+    }
+}
+1 target compilation errors:
+CS0825: The contextual keyword 'var' may only appear within a local variable declaration or in script code");
+    }
+
     [Fact]
     public async Task TestSingleCharacterStringLiteralBecomesChar_WhenExplictCastAsync()
     {