diff --git a/crates/ra_ide/src/syntax_highlighting/html.rs b/crates/ra_ide/src/syntax_highlighting/html.rs
index 4f17d10402..010db40175 100644
--- a/crates/ra_ide/src/syntax_highlighting/html.rs
+++ b/crates/ra_ide/src/syntax_highlighting/html.rs
@@ -1,11 +1,9 @@
 //! Renders a bit of code as HTML.
 
 use ra_db::SourceDatabase;
-use ra_syntax::{AstNode, TextSize};
+use ra_syntax::{AstNode, TextRange, TextSize};
 
-use crate::{FileId, RootDatabase};
-
-use super::highlight;
+use crate::{syntax_highlighting::highlight, FileId, RootDatabase};
 
 pub(crate) fn highlight_as_html(db: &RootDatabase, file_id: FileId, rainbow: bool) -> String {
     let parse = db.parse(file_id);
@@ -27,14 +25,13 @@ pub(crate) fn highlight_as_html(db: &RootDatabase, file_id: FileId, rainbow: boo
     let mut buf = String::new();
     buf.push_str(&STYLE);
     buf.push_str("<pre><code>");
-    // TODO: unusize
     for range in &ranges {
         if range.range.start() > prev_pos {
-            let curr = &text[usize::from(prev_pos)..usize::from(range.range.start())];
+            let curr = &text[TextRange::new(prev_pos, range.range.start())];
             let text = html_escape(curr);
             buf.push_str(&text);
         }
-        let curr = &text[usize::from(range.range.start())..usize::from(range.range.end())];
+        let curr = &text[TextRange::new(range.range.start(), range.range.end())];
 
         let class = range.highlight.to_string().replace('.', " ");
         let color = match (rainbow, range.binding_hash) {
@@ -48,7 +45,7 @@ pub(crate) fn highlight_as_html(db: &RootDatabase, file_id: FileId, rainbow: boo
         prev_pos = range.range.end();
     }
     // Add the remaining (non-highlighted) text
-    let curr = &text[usize::from(prev_pos)..];
+    let curr = &text[TextRange::new(prev_pos, TextSize::of(&text))];
     let text = html_escape(curr);
     buf.push_str(&text);
     buf.push_str("</code></pre>");
diff --git a/crates/ra_ide_db/src/line_index.rs b/crates/ra_ide_db/src/line_index.rs
index 7794dc9fd7..81eebc7110 100644
--- a/crates/ra_ide_db/src/line_index.rs
+++ b/crates/ra_ide_db/src/line_index.rs
@@ -1,9 +1,8 @@
 //! `LineIndex` maps flat `TextSize` offsets into `(Line, Column)`
 //! representation.
-use std::iter;
-// TODO: un TextSize
 use ra_syntax::{TextRange, TextSize};
 use rustc_hash::FxHashMap;
+use std::iter;
 use superslice::Ext;
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -42,7 +41,8 @@ impl LineIndex {
         let mut curr_col = 0.into();
         let mut line = 0;
         for c in text.chars() {
-            curr_row += TextSize::of(c);
+            let c_len = TextSize::of(c);
+            curr_row += c_len;
             if c == '\n' {
                 newlines.push(curr_row);
 
@@ -58,12 +58,11 @@ impl LineIndex {
                 continue;
             }
 
-            let char_len = TextSize::of(c);
-            if char_len > TextSize::from_usize(1) {
-                utf16_chars.push(Utf16Char { start: curr_col, end: curr_col + char_len });
+            if !c.is_ascii() {
+                utf16_chars.push(Utf16Char { start: curr_col, end: curr_col + c_len });
             }
 
-            curr_col += char_len;
+            curr_col += c_len;
         }
 
         // Save any utf-16 characters seen in the last line
@@ -102,22 +101,19 @@ impl LineIndex {
     }
 
     fn utf8_to_utf16_col(&self, line: u32, col: TextSize) -> usize {
+        let mut res: usize = col.into();
         if let Some(utf16_chars) = self.utf16_lines.get(&line) {
-            let mut correction = 0;
             for c in utf16_chars {
-                if col >= c.end {
-                    correction += usize::from(c.len()) - 1;
+                if c.end <= col {
+                    res -= usize::from(c.len()) - 1;
                 } else {
                     // From here on, all utf16 characters come *after* the character we are mapping,
                     // so we don't need to take them into account
                     break;
                 }
             }
-
-            usize::from(col) - correction
-        } else {
-            usize::from(col)
         }
+        res
     }
 
     fn utf16_to_utf8_col(&self, line: u32, col: u32) -> TextSize {
diff --git a/crates/ra_ide_db/src/search.rs b/crates/ra_ide_db/src/search.rs
index c66de4f422..599b8e5624 100644
--- a/crates/ra_ide_db/src/search.rs
+++ b/crates/ra_ide_db/src/search.rs
@@ -200,7 +200,8 @@ impl Definition {
 
         for (file_id, search_range) in search_scope {
             let text = db.file_text(file_id);
-            let search_range = search_range.unwrap_or(TextRange::up_to(TextSize::of(&text)));
+            let search_range =
+                search_range.unwrap_or(TextRange::up_to(TextSize::of(text.as_str())));
 
             let sema = Semantics::new(db);
             let tree = Lazy::new(|| sema.parse(file_id).syntax().clone());
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index 381f37f169..2303ebfdbc 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -592,7 +592,7 @@ pub fn handle_formatting(
     let crate_ids = world.analysis().crate_for(file_id)?;
 
     let file_line_index = world.analysis().file_line_index(file_id)?;
-    let end_position = TextSize::of(&file).conv_with(&file_line_index);
+    let end_position = TextSize::of(file.as_str()).conv_with(&file_line_index);
 
     let mut rustfmt = match &world.config.rustfmt {
         RustfmtConfig::Rustfmt { extra_args } => {