Roslyn : How to get unresolved types
roslyn
Solution
There are several questions here.
Q: Is it correct to use `IdentifierNameSyntax`? A: You probably want to use `SimpleNameSyntax` to handle resolving generic types. Also, you may not want to look at ALL `SimpleNameSyntax` elements. You will get false positives for things that are not actually in a type context (for example, imagine some code like `var x = Console();`
Q: Is it correct to use `GetSymbolInfo` and check for null? A: Yes, this is the right thing to check here.
Q: What is the difference between `GetSymbolInfo` and `GetTypeInfo`? A: For a syntax that represents a type name, there is no difference. However, for arbitrary expressions `GetSymbolInfo` represents the specific symbol of the expression (for example, method call, indexer access, array access, overloaded operator, etc), and `GetTypeInfo` represents the resulting type (so that you would know what type to generate if you were adding a declaration for the expression). Take for example the `InvocationExpressionSyntax` for "`myString.GetHashCode()`". `GetSymbolInfo` would return the method symbol for `GetHashCode()`, while `GetTypeInfo` would return `System.Int32`.
Problem
I am using Roslyn's September 2012 CTP. What is the most elegant way to get unresolved types in a c# code document? Eg. Type Guid requires the System namespace. Currently I have something like this: ``` var semanticModel = (SemanticModel)document.GetSemanticModel(); var tree = (SyntaxTree)document.GetSyntaxTree(); //get unresolved types var unresolvedTypes = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>() .Where(x => semanticModel.GetSymbolInfo(x).Symbol == null); ``` Is it correct to use IdentifierNameSyntax and GetSymbolInfo? Also what is the difference between GetSymbolInfo and GetTypeInfo, they both look very similar to me.