Switch to TryFrom

crates/ra_syntax/src/ast/tokens.rs

@@ -1,5 +1,7 @@
 //! There are many AstNodes, but only a few tokens, so we hand-write them here.
 
+use std::convert::{TryFrom, TryInto};
+
 use crate::{
     ast::{AstToken, Comment, RawString, String, Whitespace},
     TextRange, TextSize,
@@ -95,8 +97,8 @@ impl QuoteOffsets {
         }
 
         let start = TextSize::from(0);
-        let left_quote = TextSize::from_usize(left_quote) + TextSize::of('"');
-        let right_quote = TextSize::from_usize(right_quote);
+        let left_quote = TextSize::try_from(left_quote).unwrap() + TextSize::of('"');
+        let right_quote = TextSize::try_from(right_quote).unwrap();
         let end = TextSize::of(literal);
 
         let res = QuoteOffsets {
@@ -498,7 +500,7 @@ impl HasFormatSpecifier for String {
         let mut res = Vec::with_capacity(text.len());
         rustc_lexer::unescape::unescape_str(text, &mut |range, unescaped_char| {
             res.push((
-                TextRange::new(TextSize::from_usize(range.start), TextSize::from_usize(range.end))
+                TextRange::new(range.start.try_into().unwrap(), range.end.try_into().unwrap())
                     + offset,
                 unescaped_char,
             ))
@@ -518,11 +520,7 @@ impl HasFormatSpecifier for RawString {
 
         let mut res = Vec::with_capacity(text.len());
         for (idx, c) in text.char_indices() {
-            res.push((
-                TextRange::new(TextSize::from_usize(idx), TextSize::from_usize(idx + c.len_utf8()))
-                    + offset,
-                Ok(c),
-            ));
+            res.push((TextRange::at(idx.try_into().unwrap(), TextSize::of(c)) + offset, Ok(c)));
         }
         Some(res)
     }

crates/ra_syntax/src/fuzz.rs

@@ -1,8 +1,13 @@
 //! FIXME: write short doc here
 
-use crate::{validation, AstNode, SourceFile, TextRange, TextSize};
+use std::{
+    convert::TryInto,
+    str::{self, FromStr},
+};
+
 use ra_text_edit::AtomTextEdit;
-use std::str::{self, FromStr};
+
+use crate::{validation, AstNode, SourceFile, TextRange};
 
 fn check_file_invariants(file: &SourceFile) {
     let root = file.syntax();
@@ -35,7 +40,7 @@ impl CheckReparse {
         let text = format!("{}{}{}", PREFIX, text, SUFFIX);
         text.get(delete_start..delete_start.checked_add(delete_len)?)?; // make sure delete is a valid range
         let delete =
-            TextRange::at(TextSize::from_usize(delete_start), TextSize::from_usize(delete_len));
+            TextRange::at(delete_start.try_into().unwrap(), delete_len.try_into().unwrap());
         let edited_text =
             format!("{}{}{}", &text[..delete_start], &insert, &text[delete_start + delete_len..]);
         let edit = AtomTextEdit { delete, insert };

crates/ra_syntax/src/parsing/lexer.rs

@@ -1,6 +1,8 @@
 //! Lexer analyzes raw input string and produces lexemes (tokens).
 //! It is just a bridge to `rustc_lexer`.
 
+use std::convert::TryInto;
+
 use crate::{
     SyntaxError,
     SyntaxKind::{self, *},
@@ -28,18 +30,19 @@ pub fn tokenize(text: &str) -> (Vec<Token>, Vec<SyntaxError>) {
     let mut tokens = Vec::new();
     let mut errors = Vec::new();
 
-    let mut offset: usize = rustc_lexer::strip_shebang(text)
-        .map(|shebang_len| {
-            tokens.push(Token { kind: SHEBANG, len: TextSize::from_usize(shebang_len) });
+    let mut offset = match rustc_lexer::strip_shebang(text) {
+        Some(shebang_len) => {
+            tokens.push(Token { kind: SHEBANG, len: shebang_len.try_into().unwrap() });
             shebang_len
-        })
-        .unwrap_or(0);
+        }
+        None => 0,
+    };
 
     let text_without_shebang = &text[offset..];
 
     for rustc_token in rustc_lexer::tokenize(text_without_shebang) {
-        let token_len = TextSize::from_usize(rustc_token.len);
-        let token_range = TextRange::at(TextSize::from_usize(offset), token_len);
+        let token_len: TextSize = rustc_token.len.try_into().unwrap();
+        let token_range = TextRange::at(offset.try_into().unwrap(), token_len);
 
         let (syntax_kind, err_message) =
             rustc_token_kind_to_syntax_kind(&rustc_token.kind, &text[token_range]);
@@ -96,10 +99,9 @@ fn lex_first_token(text: &str) -> Option<(Token, Option<SyntaxError>)> {
     let rustc_token = rustc_lexer::first_token(text);
     let (syntax_kind, err_message) = rustc_token_kind_to_syntax_kind(&rustc_token.kind, text);
 
-    let token = Token { kind: syntax_kind, len: TextSize::from_usize(rustc_token.len) };
-    let optional_error = err_message.map(|err_message| {
-        SyntaxError::new(err_message, TextRange::new(0.into(), TextSize::of(text)))
-    });
+    let token = Token { kind: syntax_kind, len: rustc_token.len.try_into().unwrap() };
+    let optional_error = err_message
+        .map(|err_message| SyntaxError::new(err_message, TextRange::up_to(TextSize::of(text))));
 
     Some((token, optional_error))
 }

crates/ra_syntax/src/tests.rs

@@ -121,7 +121,7 @@ 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 = TextSize::from_usize(0);
+    let mut offset: TextSize = 0.into();
     for token in tokens {
         let token_len = token.len;
         let token_text = &text[TextRange::at(offset, token.len)];

crates/ra_syntax/src/validation.rs

@@ -2,6 +2,8 @@
 
 mod block;
 
+use std::convert::TryFrom;
+
 use rustc_lexer::unescape;
 
 use crate::{
@@ -112,7 +114,7 @@ fn validate_literal(literal: ast::Literal, acc: &mut Vec<SyntaxError>) {
 
     // FIXME: lift this lambda refactor to `fn` (https://github.com/rust-analyzer/rust-analyzer/pull/2834#discussion_r366199205)
     let mut push_err = |prefix_len, (off, err): (usize, unescape::EscapeError)| {
-        let off = token.text_range().start() + TextSize::from_usize(off + prefix_len);
+        let off = token.text_range().start() + TextSize::try_from(off + prefix_len).unwrap();
         acc.push(SyntaxError::new_at_offset(rustc_unescape_error_to_string(err), off));
     };