Add a note when trying to call a non-function

[Detegr]

r? @Manishearth

[rust-highfive]

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[Detegr]

Let's see what the build bot says about this PR. One test failed on my machine even with the master branch of Rust.
So, the error + note now looks following:

test.rs:6:5: 6:10 error: expected function, found `&str`
test.rs:6     foo();
              ^~~~~
test.rs:5:9: 5:12 note: defined here
test.rs:5     let foo="foo";

However, when the non-function is a function argument, the span is a bit funny, as it points to the function argument, but I think it is still quite informative:

test.rs:2:5: 2:8 error: expected function, found `i32`
test.rs:2     i();
              ^~~
test.rs:1:9: 1:10 note: defined here
test.rs:1 fn func(i: i32) {
                  ^

[Manishearth]

Looks good. Could you add a compile-fail test for this? (tests/compile-fail). Just some code that throws this error, with //~ERROR foo and //~NOTE baz to mark where the notes occur. Use //~^ NOTE in case you want to refer to a note that should occur on the previous line.

Run the test with make check-stage1-cfail TESTNAME=name-of-test-file

[Detegr]

Done. Should I rebase the PR to be a single commit only?

[Manishearth]

In this case two commits is fine.

But in general, feel free to rebase. git commit --amend is good too.

[Manishearth]

Do tests pass locally?

[Manishearth]

Good call on the depth check!

[Detegr]

Thanks! Some of the tests caught that one.

[Manishearth]

@bors r+

[bors]

📌 Commit 210c435 has been approved by Manishearth

[Manishearth]

Thanks!

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt