fix: Fix import insertion inserting after last comment in a file

Author: Veykril

crates/ide-db/src/imports/insert_use.rs

@@ -5,6 +5,7 @@ mod tests;
 use std::cmp::Ordering;
 
 use hir::Semantics;
+use parser::SyntaxKind;
 use syntax::{
     algo,
     ast::{self, make, AstNode, HasAttrs, HasModuleItem, HasVisibility, PathSegmentKind},
@@ -397,12 +398,16 @@ fn insert_use_(
     }
 
     // there are no imports in this file at all
+    // so put the import after all inner module attributes and possible license header comments
     if let Some(last_inner_element) = scope_syntax
         .children_with_tokens()
-        .filter(|child| match child {
+        .take_while(|child| match child {
             NodeOrToken::Node(node) => is_inner_attribute(node.clone()),
-            NodeOrToken::Token(token) => is_comment(token.clone()),
+            NodeOrToken::Token(token) => {
+                [SyntaxKind::WHITESPACE, SyntaxKind::COMMENT].contains(&token.kind())
+            }
         })
+        .filter(|child| child.as_token().map_or(true, |t| t.kind() != SyntaxKind::WHITESPACE))
         .last()
     {
         cov_mark::hit!(insert_empty_inner_attr);
@@ -439,7 +444,3 @@ fn insert_use_(
 fn is_inner_attribute(node: SyntaxNode) -> bool {
     ast::Attr::cast(node).map(|attr| attr.kind()) == Some(ast::AttrKind::Inner)
 }
-
-fn is_comment(token: SyntaxToken) -> bool {
-    ast::Comment::cast(token).is_some()
-}

crates/ide-db/src/imports/insert_use/tests.rs

@@ -5,6 +5,24 @@ use test_utils::{assert_eq_text, CURSOR_MARKER};
 
 use super::*;
 
+#[test]
+fn trailing_comment_in_empty_file() {
+    check(
+        "foo::bar",
+        r#"
+struct Struct;
+// 0 = 1
+"#,
+        r#"
+use foo::bar;
+
+struct Struct;
+// 0 = 1
+"#,
+        ImportGranularity::Crate,
+    );
+}
+
 #[test]
 fn respects_cfg_attr_fn() {
     check(