E3010

Error · Type

E3010 — Function argument count mismatch

What the compiler reports

E3010{{.*}}'Holder<i32>::len'{{.*}}expects 1 arguments, got 0

The fragments the test suite holds the compiler to. An ellipsis marks text the test does not constrain; the emitted message also carries a source location.

A program that triggers it

//
// Part of the Vx Project, under the Apache License v2.0 with LLVM Exceptions.
// See LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//
// A method named through its type, `Holder<i32>::len(..)`, resolves on a path of its own in
// the checker, and that path used to return the method's type without looking at the
// arguments at all. A call with the receiver missing type-checked clean and died in MLIR's
// verifier with a message naming neither the call nor the function. Both checks the other
// call paths make are pinned here for this one: the count, and each argument's type.

struct Holder<T> {
  v : T,
}

impl<T> Holder<T> {
  fn len(self : &Holder<T>) -> i32 {
    return 1;
  }

  fn set(self : &mut Holder<T>, x : T) -> i32 {
    self.v = x;
    return 0;
  }
}

fn main() -> i32 {
  let mut h = Holder<i32> {
    v : 0,
  };
  // The receiver is a parameter like any other; leaving it out is a count mismatch.
  let n = Holder<i32>::len();
  // The argument's type is checked against the instantiated parameter, `T` already `i32`.
  let f : f32 = 2.5;
  let m = Holder<i32>::set(&mut h, f);
  return n + m;
}

From tests/frontend/fail/static_method_call_checks_its_arguments.vx, which asserts this diagnostic on every commit.

Related