extract assist helper for getting a specific token

crates/ra_assists/src/assist_ctx.rs

@@ -5,7 +5,7 @@ use ra_db::FileRange;
 use ra_fmt::{leading_indent, reindent};
 use ra_syntax::{
     algo::{self, find_covering_element, find_node_at_offset},
-    AstNode, SourceFile, SyntaxElement, SyntaxNode, SyntaxToken, TextRange, TextUnit,
+    AstNode, SourceFile, SyntaxElement, SyntaxKind, SyntaxNode, SyntaxToken, TextRange, TextUnit,
     TokenAtOffset,
 };
 use ra_text_edit::TextEditBuilder;
@@ -111,6 +111,10 @@ impl<'a, DB: HirDatabase> AssistCtx<'a, DB> {
         self.source_file.syntax().token_at_offset(self.frange.range.start())
     }
 
+    pub(crate) fn find_token_at_offset(&self, kind: SyntaxKind) -> Option<SyntaxToken> {
+        self.token_at_offset().find(|it| it.kind() == kind)
+    }
+
     pub(crate) fn node_at_offset<N: AstNode>(&self) -> Option<N> {
         find_node_at_offset(self.source_file.syntax(), self.frange.range.start())
     }

crates/ra_assists/src/assists/flip_comma.rs

@@ -19,7 +19,7 @@ use crate::{Assist, AssistCtx, AssistId};
 // }
 // ```
 pub(crate) fn flip_comma(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
-    let comma = ctx.token_at_offset().find(|leaf| leaf.kind() == T![,])?;
+    let comma = ctx.find_token_at_offset(T![,])?;
     let prev = non_trivia_sibling(comma.clone().into(), Direction::Prev)?;
     let next = non_trivia_sibling(comma.clone().into(), Direction::Next)?;
 

crates/ra_assists/src/assists/raw_string.rs

@@ -3,17 +3,14 @@
 use hir::db::HirDatabase;
 use ra_syntax::{
     SyntaxKind::{RAW_STRING, STRING},
-    SyntaxToken, TextRange, TextUnit,
+    TextRange, TextUnit,
 };
 use rustc_lexer;
 
 use crate::{Assist, AssistCtx, AssistId};
 
 pub(crate) fn make_raw_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
-    let token = ctx.token_at_offset().right_biased()?;
+    let token = ctx.find_token_at_offset(STRING)?;
-    if token.kind() != STRING {
-        return None;
-    }
     let text = token.text().as_str();
     let usual_string_range = find_usual_string_range(text)?;
     let start_of_inside = usual_string_range.start().to_usize() + 1;
@@ -44,7 +41,7 @@ pub(crate) fn make_raw_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<As
 }
 
 pub(crate) fn make_usual_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
-    let token = raw_string_token(&ctx)?;
+    let token = ctx.find_token_at_offset(RAW_STRING)?;
     let text = token.text().as_str();
     let usual_string_range = find_usual_string_range(text)?;
     ctx.add_action(AssistId("make_usual_string"), "make usual string", |edit| {
@@ -60,7 +57,7 @@ pub(crate) fn make_usual_string(mut ctx: AssistCtx<impl HirDatabase>) -> Option<
 }
 
 pub(crate) fn add_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
-    let token = raw_string_token(&ctx)?;
+    let token = ctx.find_token_at_offset(RAW_STRING)?;
     ctx.add_action(AssistId("add_hash"), "add hash to raw string", |edit| {
         edit.target(token.text_range());
         edit.insert(token.text_range().start() + TextUnit::of_char('r'), "#");
@@ -70,7 +67,7 @@ pub(crate) fn add_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
 }
 
 pub(crate) fn remove_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
-    let token = raw_string_token(&ctx)?;
+    let token = ctx.find_token_at_offset(RAW_STRING)?;
     let text = token.text().as_str();
     if text.starts_with("r\"") {
         // no hash to remove
@@ -91,10 +88,6 @@ pub(crate) fn remove_hash(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist
     ctx.build()
 }
 
-fn raw_string_token(ctx: &AssistCtx<impl HirDatabase>) -> Option<SyntaxToken> {
-    ctx.token_at_offset().right_biased().filter(|it| it.kind() == RAW_STRING)
-}
-
 fn count_hashes(s: &str) -> usize {
     let mut max_hash_streak = 0usize;
     for idx in s.match_indices("\"#").map(|(i, _)| i) {

crates/ra_assists/src/assists/split_import.rs

@@ -8,7 +8,7 @@ use ra_syntax::{ast, AstNode, TextUnit, T};
 use crate::{Assist, AssistCtx, AssistId};
 
 pub(crate) fn split_import(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
-    let colon_colon = ctx.token_at_offset().find(|leaf| leaf.kind() == T![::])?;
+    let colon_colon = ctx.find_token_at_offset(T![::])?;
     let path = ast::Path::cast(colon_colon.parent())?;
     let top_path = successors(Some(path), |it| it.parent_path()).last()?;