Auto merge of #102068 - cjgillot:erased-lifetime-print, r=eholk

[rust.git] / clippy_lints / src / tabs_in_doc_comments.rs

diff --git a/clippy_lints/src/tabs_in_doc_comments.rs b/clippy_lints/src/tabs_in_doc_comments.rs
index 7b673e15b764a101c0c267229575a952d472433a..e223aea297fc478bf9816be4ec8f4e73a65b6391 100644 (file)
--- a/clippy_lints/src/tabs_in_doc_comments.rs
+++ b/clippy_lints/src/tabs_in_doc_comments.rs
@@ -1,22 +1,21 @@
-use crate::utils::span_lint_and_sugg;
+use clippy_utils::diagnostics::span_lint_and_sugg;
 use rustc_ast::ast;
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::{BytePos, Span};
-use std::convert::TryFrom;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks doc comments for usage of tab characters.
+    /// ### What it does
+    /// Checks doc comments for usage of tab characters.
     ///
-    /// **Why is this bad?** The rust style-guide promotes spaces instead of tabs for indentation.
+    /// ### Why is this bad?
+    /// The rust style-guide promotes spaces instead of tabs for indentation.
     /// To keep a consistent view on the source, also doc comments should not have tabs.
     /// Also, explaining ascii-diagrams containing tabs can get displayed incorrectly when the
     /// display settings of the author and reader differ.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
     /// ///
     /// /// Struct to hold two strings:
@@ -51,6 +50,7 @@
     ///    second_string: String,
     ///}
     /// ```
+    #[clippy::version = "1.41.0"]
     pub TABS_IN_DOC_COMMENTS,
     style,
     "using tabs in doc comments is not recommended"
@@ -60,14 +60,16 @@
 
 impl TabsInDocComments {
     fn warn_if_tabs_in_doc(cx: &EarlyContext<'_>, attr: &ast::Attribute) {
-        if let ast::AttrKind::DocComment(comment) = attr.kind {
+        if let ast::AttrKind::DocComment(_, comment) = attr.kind {
             let comment = comment.as_str();
 
-            for (lo, hi) in get_chunks_of_tabs(&comment) {
+            for (lo, hi) in get_chunks_of_tabs(comment) {
+                // +3 skips the opening delimiter
                 let new_span = Span::new(
-                    attr.span.lo() + BytePos(lo),
-                    attr.span.lo() + BytePos(hi),
+                    attr.span.lo() + BytePos(3 + lo),
+                    attr.span.lo() + BytePos(3 + hi),
                     attr.span.ctxt(),
+                    attr.span.parent(),
                 );
                 span_lint_and_sugg(
                     cx,
@@ -85,7 +87,7 @@ fn warn_if_tabs_in_doc(cx: &EarlyContext<'_>, attr: &ast::Attribute) {
 
 impl EarlyLintPass for TabsInDocComments {
     fn check_attribute(&mut self, cx: &EarlyContext<'_>, attribute: &ast::Attribute) {
-        Self::warn_if_tabs_in_doc(cx, &attribute);
+        Self::warn_if_tabs_in_doc(cx, attribute);
     }
 }
 
@@ -103,30 +105,32 @@ fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> {
     // tracker to decide if the last group of tabs is not closed by a non-tab character
     let mut is_active = false;
 
-    let chars_array: Vec<_> = the_str.chars().collect();
+    // Note that we specifically need the char _byte_ indices here, not the positional indexes
+    // within the char array to deal with multi-byte characters properly. `char_indices` does
+    // exactly that. It provides an iterator over tuples of the form `(byte position, char)`.
+    let char_indices: Vec<_> = the_str.char_indices().collect();
 
-    if chars_array == vec!['\t'] {
+    if let [(_, '\t')] = char_indices.as_slice() {
         return vec![(0, 1)];
     }
 
-    for (index, arr) in chars_array.windows(2).enumerate() {
-        let index = u32::try_from(index).expect(line_length_way_to_long);
-        match arr {
-            ['\t', '\t'] => {
+    for entry in char_indices.windows(2) {
+        match entry {
+            [(_, '\t'), (_, '\t')] => {
                 // either string starts with double tab, then we have to set it active,
                 // otherwise is_active is true anyway
                 is_active = true;
             },
-            [_, '\t'] => {
+            [(_, _), (index_b, '\t')] => {
                 // as ['\t', '\t'] is excluded, this has to be a start of a tab group,
                 // set indices accordingly
                 is_active = true;
-                current_start = index + 1;
+                current_start = u32::try_from(*index_b).unwrap();
             },
-            ['\t', _] => {
+            [(_, '\t'), (index_b, _)] => {
                 // this now has to be an end of the group, hence we have to push a new tuple
                 is_active = false;
-                spans.push((current_start, index + 1));
+                spans.push((current_start, u32::try_from(*index_b).unwrap()));
             },
             _ => {},
         }
@@ -136,7 +140,7 @@ fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> {
     if is_active {
         spans.push((
             current_start,
-            u32::try_from(the_str.chars().count()).expect(line_length_way_to_long),
+            u32::try_from(char_indices.last().unwrap().0 + 1).expect(line_length_way_to_long),
         ));
     }
 
@@ -147,6 +151,13 @@ fn get_chunks_of_tabs(the_str: &str) -> Vec<(u32, u32)> {
 mod tests_for_get_chunks_of_tabs {
     use super::get_chunks_of_tabs;
 
+    #[test]
+    fn test_unicode_han_string() {
+        let res = get_chunks_of_tabs(" \u{4f4d}\t");
+
+        assert_eq!(res, vec![(4, 5)]);
+    }
+
     #[test]
     fn test_empty_string() {
         let res = get_chunks_of_tabs("");