Rust checker: allow secondary spans to be ignored (#1696)

* Rust checker: allow secondary spans to be ignored
* test/handler/test_rust_handler.vader: Add tests for g:ale_rust_ignore_secondary_spans

1 files changed, 16 insertions, 0 deletions

diff --git a/doc/ale-rust.txt b/doc/ale-rust.txt
index ce5634ae..7510dfbd 100644
--- a/doc/ale-rust.txt
+++ b/doc/ale-rust.txt
@@ -198,6 +198,22 @@ g:ale_rust_ignore_error_codes                   *g:ale_rust_ignore_error_codes*
   >
   let g:ale_rust_ignore_error_codes = ['E0432', 'E0433']
 
+g:ale_rust_ignore_secondary_spans           *g:ale_rust_ignore_secondary_spans*
+                                            *b:ale_rust_ignore_secondary_spans*
+  Type: Number
+  Default: 0
+
+	When set to 1, instructs the Rust error repporting to ignore secondary
+	spans. The problem with secondary spans is that they sometimes appear in
+	error messages before the main cause of the error, for example: >
+
+  1 src/main.rs|98 col 5 error| this function takes 4 parameters but 5
+	parameters were supplied: defined here
+  2 src/main.rs|430 col 32 error| this function takes 4 parameters but 5
+	parameters were supplied: expected 4 parameters
+<
+  This is due to the sorting by line numbers. With this option set to 1,
+  the 'defined here' span will not be presented.
 
 ===============================================================================
 rustfmt                                                      *ale-rust-rustfmt*