Improve AST handling (#165)

tests/unit/Compiler/Diagnostic.cpp

@@ -104,7 +104,7 @@ TEST(Diagnostic, PCHError) {
     /// Any error in compilation will result in failure on generating PCH or PCM.
     CompilationParams params;
     params.arguments = {"clang++", "main.cpp"};
-    params.outPath = "fake.pch";
+    params.output_file = "fake.pch";
     params.add_remapped_file("main.cpp", R"(
 void foo() {}
 void foo() {}