How to compare a Microsoft.CodeAnalysis.ITypeSymbol to a System.Type

Question

I have successfully received an ITypeSymbol from a SyntaxNode by using:

SemanticModel.GetTypeInfo(sytaxNode).ConvertedType

Now I would like to

Answer 1

Based on the answer from @Tamas, I created the following recursive solution that works for closed generic types.

    static bool TypeSymbolMatchesType(ITypeSymbol typeSymbol, Type type, SemanticModel semanticModel)
    {
        return GetTypeSymbolForType(type, semanticModel).Equals(typeSymbol);
    }

    static INamedTypeSymbol GetTypeSymbolForType(Type type, SemanticModel semanticModel)
    {

        if (!type.IsConstructedGenericType)
        {
            return semanticModel.Compilation.GetTypeByMetadataName(type.FullName);
        }

        // get all typeInfo's for the Type arguments 
        var typeArgumentsTypeInfos = type.GenericTypeArguments.Select(a => GetTypeSymbolForType(a, semanticModel));

        var openType = type.GetGenericTypeDefinition();
        var typeSymbol = semanticModel.Compilation.GetTypeByMetadataName(openType.FullName);
        return typeSymbol.Construct(typeArgumentsTypeInfos.ToArray<ITypeSymbol>());
    }

Answer 2

You can get the INamedTypeSymbol for a type name with Compilation.GetTypeByMetadataName().

So try this:

semanticModel.GetTypeInfo(sytaxNode).ConvertedType.Equals(
  semanticModel.Compilation.GetTypeByMetadataName(typeof(WhateverType).FullName))

This won't work with closed generic types, for those you'll need to do a bit more. For example:

var ienumerableType = semanticModel.Compilation.GetTypeByMetadataName("System.Collections.Generic.IEnumerable`1");
var intType = semanticModel.Compilation.GetTypeByMetadataName("System.Int32");
var type = ienumerableType.Construct(intType);