Struct GraphChecker 

pub struct GraphChecker<'a> { /* private fields */ }

Lightweight graph-based checker for pre-mutation validation.

Uses the existing CodeGraphV2 and SymbolRegistry to quickly validate that mutations are likely to succeed, without running the full compiler.

Performance Target

Operation	Target	vs cargo check
Symbol exists	< 1ms	N/A
Trait impl check	< 5ms	N/A
Derive possible	< 50ms	100x faster
Full pre-check	< 100ms	50-100x faster

Implementations

impl<'a> GraphChecker<'a>

pub fn new( graph: &'a CodeGraphV2, typeflow: &'a TypeFlowGraphV2, registry: &'a SymbolRegistry, ) -> Self

Create a new GraphChecker.

pub fn with_std_impls( graph: &'a CodeGraphV2, typeflow: &'a TypeFlowGraphV2, registry: &'a SymbolRegistry, std_impls: StdImplCache, ) -> Self

Create a checker with a custom std impls cache.

pub fn check_symbol_exists(&self, name: &str) -> bool

Check if a symbol exists in the registry.

Searches both by full path and by short name.

Examples

let checker = GraphChecker::new(&graph, &registry);

// Full path lookup
assert!(checker.check_symbol_exists("my_crate::MyStruct"));

// Short name lookup (finds my_crate::MyStruct)
assert!(checker.check_symbol_exists("MyStruct"));

pub fn check_symbol_with_suggestions( &self, name: &str, ) -> Result<(), CheckError>

Check if a symbol exists and return suggestions if not.

pub fn check_symbol_unique(&self, name: &str) -> Result<SymbolId, CheckError>

Check if a symbol is unique (exactly one match).

Returns the SymbolId if exactly one symbol matches, error otherwise.

• If no symbols found: UnresolvedRef error
• If multiple symbols found: AmbiguousTarget error

Examples

let checker = GraphChecker::new(&graph, &registry);

// Unique symbol - returns SymbolId
let id = checker.check_symbol_unique("Config")?;

// Multiple Config in different modules - AmbiguousTarget error
// e.g., my_crate::config::Config and my_crate::settings::Config

pub fn check_trait_impl(&self, type_name: &str, trait_name: &str) -> bool

Check if a type implements a trait.

First checks the std impls cache, then searches the CodeGraph for Implements edges.

pub fn check_derive_possible( &self, target: &str, trait_name: &str, ) -> CheckResult

Check if a derive macro can be applied to a type.

Verifies that all fields of the type implement the required trait.

Returns

• CheckResult::Ok if derive is possible
• CheckResult::Error with missing implementations

pub fn check_field_exists( &self, type_name: &str, field_name: &str, ) -> Result<(), CheckError>

Check if a struct/type has a specific field.

Returns Ok if the field exists, Error with available fields if not.

Examples

let checker = GraphChecker::new(&graph, &registry);

// Check if Payment has a 'created_at' field
match checker.check_field_exists("Payment", "created_at") {
    Ok(()) => { /* field exists */ }
    Err(e) => { /* field not found, e contains suggestions */ }
}

pub fn check_method_exists( &self, type_name: &str, method_name: &str, ) -> Result<(), CheckError>

Check if a type has a specific method.

Searches for methods by looking up TypeName::method_name pattern and checking direct children of the type.

pub fn check_enum_variant_exists( &self, enum_name: &str, variant_name: &str, ) -> Result<(), CheckError>

Check if an enum has a specific variant.

pub fn check_struct_fields_complete( &self, struct_name: &str, provided_fields: &[&str], ) -> Result<(), CheckError>

Check if all required fields are provided for a struct literal.

Returns Ok if all fields are covered, Error with missing fields if not.

pub fn get_function_arg_count(&self, fn_name: &str) -> Option<usize>

Get the expected argument count for a function.

Returns None if the function is not found or count cannot be determined.

pub fn check_function_arg_count( &self, fn_name: &str, actual_count: usize, ) -> Result<(), CheckError>

Check if the argument count matches for a function call.

pub fn check_symbols_exist(&self, names: &[&str]) -> CheckResult

Check multiple symbols exist.

pub fn check_trait_impls(&self, checks: &[(&str, &str)]) -> CheckResult

Check multiple trait implementations.

pub fn graph(&self) -> &CodeGraphV2

Get a reference to the CodeGraphV2.

pub fn registry(&self) -> &SymbolRegistry

Get a reference to the SymbolRegistry.

pub fn std_impls(&self) -> &StdImplCache

Get a reference to the StdImplCache.

Trait Implementations

impl LightCheck for GraphChecker<'_>

fn check_symbol_exists(&self, name: &str) -> bool

Check if a symbol exists in the codebase.

fn check_trait_impl(&self, type_name: &str, trait_name: &str) -> bool

Check if a type implements a trait.

fn check_derive_possible(&self, target: &str, trait_name: &str) -> CheckResult

Check if a derive macro can be applied to a type.

fn pre_check(&self, mutation_type: &str, target: &str) -> CheckResult

Pre-check before applying a mutation.

fn post_check(&self, mutation_type: &str, target: &str) -> CheckResult

Post-check after applying a mutation.