Describe the current lifetime/label completion specifics

crates/ide_completion/src/completions/lifetime.rs

@@ -1,4 +1,12 @@
 //! Completes lifetimes and labels.
+//!
+//! These completions work a bit differently in that they are only shown when what the user types
+//! has a `'` preceding it, as our fake syntax tree is invalid otherwise(due to us not inserting a
+//! lifetime but an ident for obvious reasons).
+//! Due to this all the tests for lifetimes and labels live in this module for the time being as
+//! there is no value in lifting these out into the outline module test since they will either not
+//! show up for normal completions, or they won't show completions other than lifetimes depending
+//! on the fixture input.
 use hir::ScopeDef;
 
 use crate::{completions::Completions, context::CompletionContext};

crates/ide_completion/src/tests/predicate.rs

@@ -35,7 +35,6 @@ struct Foo<'lt, T, const C: usize> where $0 {}
 
 #[test]
 fn bound_for_type_pred() {
-    // FIXME: only show traits, macros and modules
     check(
         r#"
 struct Foo<'lt, T, const C: usize> where T: $0 {}
@@ -54,7 +53,8 @@ struct Foo<'lt, T, const C: usize> where T: $0 {}
 
 #[test]
 fn bound_for_lifetime_pred() {
-    // FIXME: should only show lifetimes here
+    // FIXME: should only show lifetimes here, that is we shouldn't get any completions here when not typing
+    // a `'`
     check(
         r#"
 struct Foo<'lt, T, const C: usize> where 'lt: $0 {}

crates/ide_completion/src/tests/type_pos.rs

@@ -142,7 +142,6 @@ fn foo<'lt, T, const C: usize>() {
 
 #[test]
 fn completes_types_and_const_in_arg_list() {
-    // FIXME: we should complete the lifetime here for now
     check_with(
         r#"
 trait Trait2 {