Factor out `pick_best_token` ide pattern into `ide_db`

1 files changed, 12 insertions, 1 deletions

diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index d96028cbc..bc21977e3 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -10,7 +10,10 @@ use std::collections::VecDeque;
 use base_db::FileId;
 use either::Either;
 use hir::{Crate, Enum, ItemInNs, MacroDef, Module, ModuleDef, Name, ScopeDef, Semantics, Trait};
-use syntax::ast::{self, make};
+use syntax::{
+    ast::{self, make},
+    SyntaxKind, SyntaxToken, TokenAtOffset,
+};
 
 use crate::RootDatabase;
 
@@ -22,6 +25,14 @@ pub fn item_name(db: &RootDatabase, item: ItemInNs) -> Option<Name> {
     }
 }
 
+/// Picks the token with the highest rank returned by the passed in function.
+pub fn pick_best_token(
+    tokens: TokenAtOffset<SyntaxToken>,
+    f: impl Fn(SyntaxKind) -> usize,
+) -> Option<SyntaxToken> {
+    tokens.max_by_key(move |t| f(t.kind()))
+}
+
 /// Converts the mod path struct into its ast representation.
 pub fn mod_path_to_ast(path: &hir::ModPath) -> ast::Path {
     let _p = profile::span("mod_path_to_ast");