Please document compiler APIs

Would it be possible to get some documentation on the compiler APIs? I am working on some TypeScript tooling, and I am using `ts.createSourceFile()` to get the AST for a TypeScript source file. However, the tree in `SourceFile.statements` is missing some information. For example, I need to know the type of an `Expression` when a `PropertyDeclaration` only has an `initializer` but no declared `type`. I have tried `TypeChecker.getContextualType()` but it always returns `undefined`; also the implementation doesn't look right. There are internal methods like `TypeChecker.getTypeOfExpression()` that look promising, but they are not visible. Also I read some mention of 'bindings', but I haven't found a way to get them. Another example is type resolution: When I encounter a `TypeNode` or something similar within the AST, I usually need to know about its declaration: Where does it come from? Is it local? Where is it imported from? Of course I can write that myself with some effort, but surely such logic already exists within the compiler, I just don't know where.