Account for type error on method arg caused by earlier inference

Account for type error on method arg caused by earlier inference

```rust
fn main() {
    let v = Vec::new();
    v.push(0);
    v.push(0);
    v.push("");
}
```

now produces

```
error[E0308]: mismatched types
  --> $DIR/point-at-inference-3.rs:6:12
   |
LL |     v.push(0);
   |            - this is of type `{integer}`, which makes `v` to be inferred as `Vec<{integer}>`
...
LL |     v.push("");
   |       ---- ^^ expected integer, found `&str`
   |       |
   |       arguments to this function are incorrect
   |
note: associated function defined here
  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
```