From 745c600617bc5dd1405cb53b1f79e5f421d62b0f Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Mon, 30 Oct 2023 10:13:12 +0000 Subject: [PATCH 1/2] Talk about `gen fn` in diagnostics about `gen fn` --- compiler/rustc_parse/messages.ftl | 4 ++-- compiler/rustc_parse/src/errors.rs | 4 ++-- compiler/rustc_parse/src/parser/item.rs | 2 +- tests/ui/coroutine/gen_fn.e2024.stderr | 4 ++-- tests/ui/coroutine/gen_fn.rs | 2 +- 5 files changed, 8 insertions(+), 8 deletions(-) diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl index 9bedd7b8a338a..9ba1f0a5df914 100644 --- a/compiler/rustc_parse/messages.ftl +++ b/compiler/rustc_parse/messages.ftl @@ -278,8 +278,8 @@ parse_found_expr_would_be_stmt = expected expression, found `{$token}` parse_function_body_equals_expr = function body cannot be `= expression;` .suggestion = surround the expression with `{"{"}` and `{"}"}` instead of `=` and `;` -parse_gen_block = `gen` blocks are not yet implemented - .help = only the keyword is reserved for now +parse_gen_fn = `gen` functions are not yet implemented + .help = for now you can use `gen {"{}"}` blocks and return `impl Iterator` instead parse_generic_args_in_pat_require_turbofish_syntax = generic args in patterns require the turbofish syntax diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs index c0e94d15da0bf..e5cd91a32a7bf 100644 --- a/compiler/rustc_parse/src/errors.rs +++ b/compiler/rustc_parse/src/errors.rs @@ -521,9 +521,9 @@ pub(crate) struct CatchAfterTry { } #[derive(Diagnostic)] -#[diag(parse_gen_block)] +#[diag(parse_gen_fn)] #[help] -pub(crate) struct GenBlock { +pub(crate) struct GenFn { #[primary_span] pub span: Span, } diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs index a9f456d64cd11..55ad3f42938b4 100644 --- a/compiler/rustc_parse/src/parser/item.rs +++ b/compiler/rustc_parse/src/parser/item.rs @@ -2372,7 +2372,7 @@ impl<'a> Parser<'a> { } if let Gen::Yes { span, .. } = genness { - self.sess.emit_err(errors::GenBlock { span }); + self.sess.emit_err(errors::GenFn { span }); } if !self.eat_keyword_case(kw::Fn, case) { diff --git a/tests/ui/coroutine/gen_fn.e2024.stderr b/tests/ui/coroutine/gen_fn.e2024.stderr index 41bd04d976912..388e10fd65e44 100644 --- a/tests/ui/coroutine/gen_fn.e2024.stderr +++ b/tests/ui/coroutine/gen_fn.e2024.stderr @@ -1,10 +1,10 @@ -error: `gen` blocks are not yet implemented +error: `gen` functions are not yet implemented --> $DIR/gen_fn.rs:4:1 | LL | gen fn foo() {} | ^^^ | - = help: only the keyword is reserved for now + = help: for now you can use `gen {}` blocks and return `impl Iterator` instead error: aborting due to previous error diff --git a/tests/ui/coroutine/gen_fn.rs b/tests/ui/coroutine/gen_fn.rs index 9566660dfb566..da515f263b00a 100644 --- a/tests/ui/coroutine/gen_fn.rs +++ b/tests/ui/coroutine/gen_fn.rs @@ -3,6 +3,6 @@ gen fn foo() {} //[none]~^ ERROR: expected one of `#`, `async`, `const`, `default`, `extern`, `fn`, `pub`, `unsafe`, or `use`, found `gen` -//[e2024]~^^ ERROR: `gen` blocks are not yet implemented +//[e2024]~^^ ERROR: `gen` functions are not yet implemented fn main() {} From bc926f7c33c5fa12a5d42c1c597245d047346fd6 Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Mon, 30 Oct 2023 10:23:57 +0000 Subject: [PATCH 2/2] Add a custom panic message for resuming `gen` blocks after they panicked --- compiler/rustc_middle/messages.ftl | 2 ++ compiler/rustc_middle/src/mir/terminator.rs | 3 +-- tests/ui/coroutine/gen_block_panic.rs | 25 +++++++++++++++++++++ tests/ui/coroutine/gen_block_panic.stderr | 12 ++++++++++ 4 files changed, 40 insertions(+), 2 deletions(-) create mode 100644 tests/ui/coroutine/gen_block_panic.rs create mode 100644 tests/ui/coroutine/gen_block_panic.stderr diff --git a/compiler/rustc_middle/messages.ftl b/compiler/rustc_middle/messages.ftl index 37ff5bcf1e2da..27d555d7e26c7 100644 --- a/compiler/rustc_middle/messages.ftl +++ b/compiler/rustc_middle/messages.ftl @@ -12,6 +12,8 @@ middle_assert_coroutine_resume_after_return = coroutine resumed after completion middle_assert_divide_by_zero = attempt to divide `{$val}` by zero +middle_assert_gen_resume_after_panic = `gen` fn or block cannot be further iterated on after it panicked + middle_assert_misaligned_ptr_deref = misaligned pointer dereference: address must be a multiple of {$required} but is {$found} diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs index c2aa015f4b7e7..9dfbe1733cc51 100644 --- a/compiler/rustc_middle/src/mir/terminator.rs +++ b/compiler/rustc_middle/src/mir/terminator.rs @@ -250,8 +250,7 @@ impl AssertKind { middle_assert_coroutine_resume_after_return } ResumedAfterPanic(CoroutineKind::Async(_)) => middle_assert_async_resume_after_panic, - // FIXME(gen_blocks): custom error message for `gen` blocks - ResumedAfterPanic(CoroutineKind::Gen(_)) => middle_assert_async_resume_after_panic, + ResumedAfterPanic(CoroutineKind::Gen(_)) => middle_assert_gen_resume_after_panic, ResumedAfterPanic(CoroutineKind::Coroutine) => { middle_assert_coroutine_resume_after_panic } diff --git a/tests/ui/coroutine/gen_block_panic.rs b/tests/ui/coroutine/gen_block_panic.rs new file mode 100644 index 0000000000000..33e2b4b265a11 --- /dev/null +++ b/tests/ui/coroutine/gen_block_panic.rs @@ -0,0 +1,25 @@ +//compile-flags: --edition 2024 -Zunstable-options +// run-pass +#![feature(gen_blocks)] + +fn main() { + let mut iter = gen { + yield 42; + panic!("foo"); + yield 69; //~ WARN: unreachable statement + }; + assert_eq!(iter.next(), Some(42)); + let mut tmp = std::panic::AssertUnwindSafe(&mut iter); + match std::panic::catch_unwind(move || tmp.next()) { + Ok(_) => unreachable!(), + Err(err) => assert_eq!(*err.downcast::<&'static str>().unwrap(), "foo"), + } + + match std::panic::catch_unwind(move || iter.next()) { + Ok(_) => unreachable!(), + Err(err) => assert_eq!( + *err.downcast::<&'static str>().unwrap(), + "`gen fn` should just keep returning `None` after panicking", + ), + } +} diff --git a/tests/ui/coroutine/gen_block_panic.stderr b/tests/ui/coroutine/gen_block_panic.stderr new file mode 100644 index 0000000000000..33d2a95cab8bc --- /dev/null +++ b/tests/ui/coroutine/gen_block_panic.stderr @@ -0,0 +1,12 @@ +warning: unreachable statement + --> $DIR/gen_block_panic.rs:9:9 + | +LL | panic!("foo"); + | ------------- any code following this expression is unreachable +LL | yield 69; + | ^^^^^^^^^ unreachable statement + | + = note: `#[warn(unreachable_code)]` on by default + +warning: 1 warning emitted +