Merge #3570

3570: Remove some TextUnit->usize escapees r=matklad a=CAD97

As spotted during [a review of all uses of `text_unit::TextUnit::to_usize`](https://github.com/rust-analyzer/text_unit/pull/12#issuecomment-598512370). Legitimate uses do remain.

Co-authored-by: CAD97 <[email protected]>

7 files changed, 31 insertions, 27 deletions

diff --git a/crates/ra_assists/src/lib.rs b/crates/ra_assists/src/lib.rs
index 50a15f978..62fadcddd 100644
--- a/crates/ra_assists/src/lib.rs
+++ b/crates/ra_assists/src/lib.rs
@@ -235,7 +235,7 @@ mod helpers {
             (Some(assist), ExpectedResult::Target(target)) => {
                 let action = assist.0[0].action.clone().unwrap();
                 let range = action.target.expect("expected target on action");
-                assert_eq_text!(&before[range.start().to_usize()..range.end().to_usize()], target);
+                assert_eq_text!(&before[range], target);
             }
             (Some(_), ExpectedResult::NotApplicable) => panic!("assist should not be applicable!"),
             (None, ExpectedResult::After(_)) | (None, ExpectedResult::Target(_)) => {
diff --git a/crates/ra_ide/src/syntax_tree.rs b/crates/ra_ide/src/syntax_tree.rs
index 55966daf3..f58e436d1 100644
--- a/crates/ra_ide/src/syntax_tree.rs
+++ b/crates/ra_ide/src/syntax_tree.rs
@@ -5,7 +5,7 @@ use ra_ide_db::RootDatabase;
 use ra_syntax::{
     algo, AstNode, NodeOrToken, SourceFile,
     SyntaxKind::{RAW_STRING, STRING},
-    SyntaxToken, TextRange,
+    SyntaxToken, TextRange, TextUnit,
 };
 
 pub use ra_db::FileId;
@@ -56,19 +56,23 @@ fn syntax_tree_for_token(node: &SyntaxToken, text_range: TextRange) -> Option<St
     let start = text_range.start() - node_range.start();
 
     // how many characters we have selected
-    let len = text_range.len().to_usize();
+    let len = text_range.len();
 
-    let node_len = node_range.len().to_usize();
+    let node_len = node_range.len();
 
-    let start = start.to_usize();
+    let start = start;
 
     // We want to cap our length
     let len = len.min(node_len);
 
     // Ensure our slice is inside the actual string
-    let end = if start + len < text.len() { start + len } else { text.len() - start };
+    let end = if start + len < TextUnit::of_str(&text) {
+        start + len
+    } else {
+        TextUnit::of_str(&text) - start
+    };
 
-    let text = &text[start..end];
+    let text = &text[TextRange::from_to(start, end)];
 
     // Remove possible extra string quotes from the start
     // and the end of the string
diff --git a/crates/ra_ide_db/src/line_index.rs b/crates/ra_ide_db/src/line_index.rs
index b9db5c276..8ae745ff2 100644
--- a/crates/ra_ide_db/src/line_index.rs
+++ b/crates/ra_ide_db/src/line_index.rs
@@ -59,7 +59,7 @@ impl LineIndex {
             }
 
             let char_len = TextUnit::of_char(c);
-            if char_len.to_usize() > 1 {
+            if char_len > TextUnit::from_usize(1) {
                 utf16_chars.push(Utf16Char { start: curr_col, end: curr_col + char_len });
             }
 
@@ -101,12 +101,12 @@ impl LineIndex {
             .filter(|it| !it.is_empty())
     }
 
-    fn utf8_to_utf16_col(&self, line: u32, mut col: TextUnit) -> usize {
+    fn utf8_to_utf16_col(&self, line: u32, col: TextUnit) -> usize {
         if let Some(utf16_chars) = self.utf16_lines.get(&line) {
-            let mut correction = TextUnit::from_usize(0);
+            let mut correction = 0;
             for c in utf16_chars {
                 if col >= c.end {
-                    correction += c.len() - TextUnit::from_usize(1);
+                    correction += c.len().to_usize() - 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
@@ -114,10 +114,10 @@ impl LineIndex {
                 }
             }
 
-            col -= correction;
+            col.to_usize() - correction
+        } else {
+            col.to_usize()
         }
-
-        col.to_usize()
     }
 
     fn utf16_to_utf8_col(&self, line: u32, col: u32) -> TextUnit {
diff --git a/crates/ra_ide_db/src/line_index_utils.rs b/crates/ra_ide_db/src/line_index_utils.rs
index 75a498151..2ebbabdc6 100644
--- a/crates/ra_ide_db/src/line_index_utils.rs
+++ b/crates/ra_ide_db/src/line_index_utils.rs
@@ -145,7 +145,7 @@ impl Iterator for OffsetStepIter<'_> {
                     Some((next, next_offset))
                 } else {
                     let char_len = TextUnit::of_char(c);
-                    if char_len.to_usize() > 1 {
+                    if char_len > TextUnit::from_usize(1) {
                         let start = self.offset + TextUnit::from_usize(i);
                         let end = start + char_len;
                         let next = Step::Utf16Char(TextRange::from_to(start, end));
diff --git a/crates/ra_syntax/src/parsing/lexer.rs b/crates/ra_syntax/src/parsing/lexer.rs
index f2684c852..d1baaa607 100644
--- a/crates/ra_syntax/src/parsing/lexer.rs
+++ b/crates/ra_syntax/src/parsing/lexer.rs
@@ -65,7 +65,7 @@ pub fn tokenize(text: &str) -> (Vec<Token>, Vec<SyntaxError>) {
 /// Beware that unescape errors are not checked at tokenization time.
 pub fn lex_single_syntax_kind(text: &str) -> Option<(SyntaxKind, Option<SyntaxError>)> {
     lex_first_token(text)
-        .filter(|(token, _)| token.len.to_usize() == text.len())
+        .filter(|(token, _)| token.len == TextUnit::of_str(text))
         .map(|(token, error)| (token.kind, error))
 }
 
@@ -75,7 +75,7 @@ pub fn lex_single_syntax_kind(text: &str) -> Option<(SyntaxKind, Option<SyntaxEr
 /// Beware that unescape errors are not checked at tokenization time.
 pub fn lex_single_valid_syntax_kind(text: &str) -> Option<SyntaxKind> {
     lex_first_token(text)
-        .filter(|(token, error)| !error.is_some() && token.len.to_usize() == text.len())
+        .filter(|(token, error)| !error.is_some() && token.len == TextUnit::of_str(text))
         .map(|(token, _error)| token.kind)
 }
 
diff --git a/crates/ra_syntax/src/tests.rs b/crates/ra_syntax/src/tests.rs
index 912e6aec0..d331d541e 100644
--- a/crates/ra_syntax/src/tests.rs
+++ b/crates/ra_syntax/src/tests.rs
@@ -5,7 +5,7 @@ use std::{
 
 use test_utils::{collect_tests, dir_tests, project_dir, read_text};
 
-use crate::{fuzz, tokenize, SourceFile, SyntaxError, Token};
+use crate::{fuzz, tokenize, SourceFile, SyntaxError, TextRange, TextUnit, Token};
 
 #[test]
 fn lexer_tests() {
@@ -120,11 +120,11 @@ fn assert_errors_are_absent(errors: &[SyntaxError], path: &Path) {
 
 fn dump_tokens_and_errors(tokens: &[Token], errors: &[SyntaxError], text: &str) -> String {
     let mut acc = String::new();
-    let mut offset = 0;
+    let mut offset = TextUnit::from_usize(0);
     for token in tokens {
-        let token_len = token.len.to_usize();
-        let token_text = &text[offset..offset + token_len];
-        offset += token_len;
+        let token_len = token.len;
+        let token_text = &text[TextRange::offset_len(offset, token.len)];
+        offset += token.len;
         writeln!(acc, "{:?} {} {:?}", token.kind, token_len, token_text).unwrap();
     }
     for err in errors {
diff --git a/crates/ra_text_edit/src/text_edit.rs b/crates/ra_text_edit/src/text_edit.rs
index 3291ada42..5c37a08a8 100644
--- a/crates/ra_text_edit/src/text_edit.rs
+++ b/crates/ra_text_edit/src/text_edit.rs
@@ -63,12 +63,12 @@ impl TextEdit {
     }
 
     pub fn apply(&self, text: &str) -> String {
-        let mut total_len = text.len();
+        let mut total_len = TextUnit::of_str(text);
         for atom in self.atoms.iter() {
-            total_len += atom.insert.len();
-            total_len -= (atom.delete.end() - atom.delete.start()).to_usize();
+            total_len += TextUnit::of_str(&atom.insert);
+            total_len -= atom.delete.end() - atom.delete.start();
         }
-        let mut buf = String::with_capacity(total_len);
+        let mut buf = String::with_capacity(total_len.to_usize());
         let mut prev = 0;
         for atom in self.atoms.iter() {
             let start = atom.delete.start().to_usize();
@@ -80,7 +80,7 @@ impl TextEdit {
             prev = end;
         }
         buf.push_str(&text[prev..text.len()]);
-        assert_eq!(buf.len(), total_len);
+        assert_eq!(TextUnit::of_str(&buf), total_len);
         buf
     }