Parse Method Calls

A method call is a kind of expression, and can come in both receiver and qualified form:

#![allow(unused)]
fn main() {
// Both of these do the same thing!
receiver.method(args);
Struct::method(&receiver, args);
}

In order to parse a method call, you must first have an Expr. In this case we'll first implement LateLintPass's check_expr() method, but you can get an Expr through several other means:

#![allow(unused)]
fn main() {
impl<'tcx> LateLintPass<'tcx> for MyLintPass {
    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
        // ...
    }
}
}

Once you have an Expr, you can parse method calls with the MethodCall utility:

#![allow(unused)]
fn main() {
use crate::utils::hir_parse::MethodCall;

fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
    // Extract a `MethodCall` from the `Expr` if it is a method call.
    if let Some(MethodCall { receiver, args, .. }) = MethodCall::try_from(cx, expr) {
        // ...
    }
}
}

MethodCall::try_from() returns an Option, and will only be Some if the expression was actually a method call. Take a look at MethodCall's fields to see what properties are available.