Handle str literals written with `'` lexed as lifetime #122217

estebank · 2024-03-09T00:36:24Z

Given 'hello world' and `'1 str', provide a structured suggestion for a valid string literal:

error[E0762]: unterminated character literal
  --> $DIR/lex-bad-str-literal-as-char-3.rs:2:26
   |
LL |     println!('hello world');
   |                          ^^^^
   |
help: if you meant to write a `str` literal, use double quotes
   |
LL |     println!("hello world");
   |              ~           ~

error[E0762]: unterminated character literal
  --> $DIR/lex-bad-str-literal-as-char-1.rs:2:20
   |
LL |     println!('1 + 1');
   |                    ^^^^
   |
help: if you meant to write a `str` literal, use double quotes
   |
LL |     println!("1 + 1");
   |              ~     ~

Fix #119685.

rustbot · 2024-03-09T00:36:31Z

r? @lcnr

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lcnr · 2024-03-11T09:21:25Z

r? compiler

fmease

Looks good overall, thanks! I have a couple of minor suggestions and a question. And of course, the negative overflow needs to be fixed.

If I follow the code correctly, for r'hello world' (a meant-to-be raw string literal), we will still emit two errors (prefix `r` is unknown & unterminated character literal). It's probably fine as-is but we could also think about suppressing the unknown prefix error if feasible 🤔

compiler/rustc_parse/src/lexer/mod.rs

tests/ui/lexer/lex-bad-str-literal-as-char-2.stderr

fmease · 2024-03-11T12:29:59Z

tests/ui/lexer/lex-bad-str-literal-as-char-2.rs

Could you check if this duplicates any preexisting UI tests whose stderr contains character literal may only contain one codepoint / if you meant to write a `str` literal, use double quotes and if so remove one in favor of the other or consolidate them?

The closest one to duplicating this case is the println!('●●') one, but I feel that having one for an unicode char and another for a whitespace is worthwhile keeping. Also, these are all separate files because lexer errors are early enough that the swallow later errors (so earlier lexer errors would silence later ones).

tests/ui/lexer/lex-bad-str-literal-as-char-3.rs

… in 2021 edition

fmease

I have two questions, otherwise r=me with or without nits addressed at your convenience. Sorry for the delay :| and thanks for taking this on! :)

fmease · 2024-03-22T16:26:10Z

tests/ui/lexer/lex-bad-str-literal-as-char-3.rs

 fn main() {
-    println!('hello world'); //~ ERROR unterminated character literal
+    println!('hello world');
+    //[rust2015,rust2018,rust2021]~^ ERROR unterminated character literal


Could be simplified to

Suggested change

//[rust2015,rust2018,rust2021]~^ ERROR unterminated character literal

//~^ ERROR unterminated character literal

but not blocking.

fmease · 2024-03-22T16:31:19Z

compiler/rustc_lexer/src/cursor.rs

@@ -59,6 +59,15 @@ impl<'a> Cursor<'a> {
        iter.next().unwrap_or(EOF_CHAR)
    }

+    /// Peeks the third symbol from the input stream without consuming it.
+    pub fn third(&self) -> char {


Since second and third are exclusively used in the error path if I'm not mistaken (haven't double-checked), perf shouldn't matter that much and we can maybe avoid introducing those helpers? Idk, do we have access to self.chars in the parser? If so, we could just use .clone().nth(N), right?

self.chars is private to the lexer. I initially made it public, but given it is used only in one place it felt better to introduce the method. But then we could instead just have an nth method that expands to .clone().nth(N) instead.

fmease · 2024-03-22T16:34:09Z

compiler/rustc_parse/src/lexer/mod.rs

+            let err = errors::UnknownPrefix { span: prefix_span, prefix, sugg };
+            if silence {
+                self.dcx().create_err(err).delay_as_bug();
+            } else {
+                self.dcx().emit_err(err);
+            }


I would probably structure it a bit differently, namely let err = create_err(); if silence { err.delay_as_bug() } else { err.emit() } but that's just a difference in taste. Definitely not blocking.

fmease · 2024-03-22T16:41:20Z

compiler/rustc_parse/src/lexer/unescape_error_reporting.rs

@@ -95,7 +95,7 @@ pub(crate) fn emit_unescape_error(
                    }
                    escaped.push(c);
                }
-                if escaped.len() != lit.len() {
+                if escaped.len() != lit.len() || full_lit_span.is_empty() {


I understand that this prevents the negative overflow & that makes sense but why wasn't this an issue before? Don't have the time to dig deep into the code myself.

Before we were replacing the full span with the new string (instead of doing BytePos math). We just end up with an invalid suggestion that won't be displayed.

fmease · 2024-03-23T18:17:03Z

Okay, seems fine as is.

@bors r+ rollup

bors · 2024-03-23T18:17:05Z

📌 Commit f4d30b1 has been approved by fmease

It is now in the queue for this repository.

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#116016 (Soft-destabilize `RustcEncodable` & `RustcDecodable`, remove from prelude in next edition) - rust-lang#121281 (regression test for rust-lang#103626) - rust-lang#122168 (Fix validation on substituted callee bodies in MIR inliner) - rust-lang#122217 (Handle str literals written with `'` lexed as lifetime) - rust-lang#122379 (transmute: caution against int2ptr transmutation) - rust-lang#122907 (Uniquify `ReError` on input mode in canonicalizer) - rust-lang#122942 (Add test in higher ranked subtype) - rust-lang#122943 (add a couple more ice tests) r? `@ghost` `@rustbot` modify labels: rollup

…kingjubilee Rollup of 13 pull requests Successful merges: - rust-lang#121281 (regression test for rust-lang#103626) - rust-lang#121940 (Mention Register Size in `#[warn(asm_sub_register)]`) - rust-lang#122217 (Handle str literals written with `'` lexed as lifetime) - rust-lang#122379 (transmute: caution against int2ptr transmutation) - rust-lang#122460 (Rework rmake support library API) - rust-lang#122797 (Fix compile of wasm64-unknown-unknown target) - rust-lang#122875 (CFI: Support self_cell-like recursion) - rust-lang#122879 (CFI: Strip auto traits off Virtual calls) - rust-lang#122895 (add some ice tests 5xxxx to 9xxxx) - rust-lang#122907 (Uniquify `ReError` on input mode in canonicalizer) - rust-lang#122923 (In `pretty_print_type()`, print `async fn` futures' paths instead of spans.) - rust-lang#122942 (Add test in higher ranked subtype) - rust-lang#122963 (core/panicking: fix outdated comment) r? `@ghost` `@rustbot` modify labels: rollup

…iaskrgr Rollup of 9 pull requests Successful merges: - rust-lang#121281 (regression test for rust-lang#103626) - rust-lang#122168 (Fix validation on substituted callee bodies in MIR inliner) - rust-lang#122217 (Handle str literals written with `'` lexed as lifetime) - rust-lang#122379 (transmute: caution against int2ptr transmutation) - rust-lang#122840 (`rustdoc --test`: Prevent reaching the maximum size of command-line by using files for arguments if there are too many) - rust-lang#122907 (Uniquify `ReError` on input mode in canonicalizer) - rust-lang#122942 (Add test in higher ranked subtype) - rust-lang#122943 (add a couple more ice tests) - rust-lang#122963 (core/panicking: fix outdated comment) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#122217 - estebank:issue-119685, r=fmease Handle str literals written with `'` lexed as lifetime Given `'hello world'` and `'1 str', provide a structured suggestion for a valid string literal: ``` error[E0762]: unterminated character literal --> $DIR/lex-bad-str-literal-as-char-3.rs:2:26 | LL | println!('hello world'); | ^^^^ | help: if you meant to write a `str` literal, use double quotes | LL | println!("hello world"); | ~ ~ ``` ``` error[E0762]: unterminated character literal --> $DIR/lex-bad-str-literal-as-char-1.rs:2:20 | LL | println!('1 + 1'); | ^^^^ | help: if you meant to write a `str` literal, use double quotes | LL | println!("1 + 1"); | ~ ~ ``` Fix rust-lang#119685.

…iaskrgr Rollup of 9 pull requests Successful merges: - rust-lang#121281 (regression test for rust-lang#103626) - rust-lang#122168 (Fix validation on substituted callee bodies in MIR inliner) - rust-lang#122217 (Handle str literals written with `'` lexed as lifetime) - rust-lang#122379 (transmute: caution against int2ptr transmutation) - rust-lang#122840 (`rustdoc --test`: Prevent reaching the maximum size of command-line by using files for arguments if there are too many) - rust-lang#122907 (Uniquify `ReError` on input mode in canonicalizer) - rust-lang#122942 (Add test in higher ranked subtype) - rust-lang#122943 (add a couple more ice tests) - rust-lang#122963 (core/panicking: fix outdated comment) r? `@ghost` `@rustbot` modify labels: rollup

Don't suggest turning non-char-literal exprs of ty `char` into string literals Fixes rust-lang#125595. Fixes rust-lang#125081. r? estebank (rust-lang#122217) or compiler

Rollup merge of rust-lang#125640 - fmease:plz-no-stringify, r=estebank Don't suggest turning non-char-literal exprs of ty `char` into string literals Fixes rust-lang#125595. Fixes rust-lang#125081. r? estebank (rust-lang#122217) or compiler

rustbot assigned lcnr Mar 9, 2024

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 9, 2024

estebank force-pushed the issue-119685 branch from b4de21f to fc1339b Compare March 9, 2024 00:37

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estebank added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Mar 14, 2024

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estebank added 6 commits March 17, 2024 23:35

Use shorter span for existing ' -> " structured suggestion

4a10b01

review comment: str -> string in messages

999a0dc

Extend test to trigger on 2015, 2018 and 2021 editions

6f388ef

Silence redundant error on char literal that was meant to be a string…

ea1883d

… in 2021 edition

fix rustdoc test

f4d30b1

estebank force-pushed the issue-119685 branch from 11e9cb8 to f4d30b1 Compare March 17, 2024 23:46

fmease approved these changes Mar 22, 2024

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 23, 2024

matthiaskrgr mentioned this pull request Mar 23, 2024

Rollup of 8 pull requests #122959

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matthiaskrgr mentioned this pull request Mar 24, 2024

Rollup of 9 pull requests #122966

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workingjubilee mentioned this pull request Mar 24, 2024

Rollup of 13 pull requests #122967

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workingjubilee mentioned this pull request Mar 24, 2024

Rollup of 14 pull requests #122973

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bors merged commit 1164c27 into rust-lang:master Mar 24, 2024
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rustbot added this to the 1.79.0 milestone Mar 24, 2024

matthiaskrgr mentioned this pull request Mar 26, 2024

ICE: prefix is unknown #123079

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compiler-errors mentioned this pull request Mar 30, 2024

Fix invalid silencing of parsing error #123223

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matthiaskrgr mentioned this pull request May 13, 2024

ICE: assertion failed: bpos.to_u32() >= mbc.pos.to_u32() + mbc.bytes as u32 #125081

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This was referenced May 28, 2024

Don't suggest turning non-char-literal exprs of ty char into string literals #125640

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Incorrectly suggests replacing end characters of function call with double quotes #125595

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Handle str literals written with `'` lexed as lifetime #122217

Handle str literals written with `'` lexed as lifetime #122217

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	//[rust2015,rust2018,rust2021]~^ ERROR unterminated character literal
	//~^ ERROR unterminated character literal

Handle str literals written with ' lexed as lifetime #122217

Handle str literals written with ' lexed as lifetime #122217

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Handle str literals written with `'` lexed as lifetime #122217

Handle str literals written with `'` lexed as lifetime #122217

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