Implement C++ backend in Rust porting logic from legacy script

pdl-compiler/scripts/generate_cxx_backend_tests.py

@@ -83,7 +83,8 @@ def check_members(decl: ast.Declaration, var: str, expected: object) -> List[str
                 checks.append(f"ASSERT_TRUE(!{get_field(decl, var, id)}.has_value());")
 
             elif isinstance(field, ast.TypedefField) and field.cond and value is not None:
-                checks.append(f"{field.type_id} const& {field_var} = {get_field(decl, var, id)}.value();")
+                checks.append(f"auto opt_{field_var} = {get_field(decl, var, id)};")
+                checks.append(f"{field.type_id} const& {field_var} = opt_{field_var}.value();")
                 checks.extend(check_members(field.type, field_var, value))
 
             elif isinstance(field, ast.TypedefField):

pdl-compiler/src/analyzer.rs

@@ -1934,7 +1934,7 @@ mod test {
             let mut db = ast::SourceDatabase::new();
             let file = parse_inline(&mut db, "stdin", $text.to_owned()).expect("parsing failure");
             let result = analyzer::analyze(&file);
-            assert!(matches!(result, Err(_)));
+            assert!(result.is_err());
             let diagnostics = result.err().unwrap();
             let mut buffer = termcolor::Buffer::no_color();
             let _ = diagnostics.emit(&db, &mut buffer);

pdl-compiler/src/backends.rs

@@ -14,6 +14,7 @@
 
 //! Compiler backends.
 
+pub mod cxx;
 #[cfg(feature = "java")]
 pub mod java;
 pub mod json;