Panic on relm macro with "there must be a else here" message
#3741
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I-ICE
Issue: Clippy panicked, giving an Internal Compilation Error (ICE) ❄️
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phansch
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I-ICE
|
Small repro proc-derive for what I think is the same issue: //test_derive/src/lib.rs
//dependencies for test_derive:
//proc-macro2 = "0.4"
//quote = "0.6"
//syn = "0.15"
extern crate proc_macro;
use quote::quote_spanned;
#[proc_macro_derive(Test)]
pub fn derive_test(input_stream: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input: syn::DeriveInput = syn::parse(input_stream).unwrap();
let name = input.ident;
let span = name.span();
let mut cases = Vec::new();
for i in 0..3 {
cases.push(quote_spanned!{span=>
if n == #i {
println!("case {}", #i);
} else
});
}
quote_spanned!(span=>
fn code(n: i32) {
#(#cases)*
{
println!("no case matched");
}
}
).into()
}//src/main.rs
use test_derive::Test;
#[derive(Test)]
struct Test();
fn main() {
code(2);
}Both splitting the quote into multiple pieces and applying a span ( |
|
Minimized example from @SNCPlay42's code: //test_macro/src/lib.rs
//dependencies for test_macro:
//proc-macro2 = "0.4"
//quote = "0.6"
extern crate proc_macro;
use quote::{quote, quote_spanned};
#[proc_macro]
pub fn macro_test(input_stream: proc_macro::TokenStream) -> proc_macro::TokenStream {
let first_token = input_stream.into_iter().next().unwrap();
let span: proc_macro2::Span = first_token.span().into();
let clause = quote_spanned!(span=> {});
quote!(
fn code() {
if true #clause else #clause
}
).into()
}
//src/lib.rs
test_macro::macro_test!(2);Both if and else clauses need to have a span from the input stream to trigger ICE. |
|
A zero crates.io dependency version of the minimal example above: //test_macro/src/lib.rs
//no dependencies for test_macro:
extern crate proc_macro;
use proc_macro::{Delimiter, Group, Ident, Span, TokenStream, TokenTree};
use std::iter::FromIterator;
#[proc_macro]
pub fn macro_test(input_stream: TokenStream) -> TokenStream {
let first_token = input_stream.into_iter().next().unwrap();
let span = first_token.span();
TokenStream::from_iter(vec![
TokenTree::Ident(Ident::new("fn", Span::call_site())),
TokenTree::Ident(Ident::new("code", Span::call_site())),
TokenTree::Group(Group::new(Delimiter::Parenthesis, TokenStream::new())),
TokenTree::Group(Group::new(Delimiter::Brace, {
let mut clause = Group::new(Delimiter::Brace, TokenStream::new());
clause.set_span(span);
TokenStream::from_iter(vec![
TokenTree::Ident(Ident::new("if", Span::call_site())),
TokenTree::Ident(Ident::new("true", Span::call_site())),
TokenTree::Group(clause.clone()),
TokenTree::Ident(Ident::new("else", Span::call_site())),
TokenTree::Group(clause.clone()),
])
})),
])
}
//src/lib.rs
test_macro::macro_test!(2); |
anelson
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this issue
Apr 3, 2019
phansch
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to phansch/compiletest-rs
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Apr 7, 2019
Taken from work on rust-lang/rust-clippy#3741. I think this is a useful test to have because it tests * the `run-pass` header * the `aux-build` header, building auxiliary files * the `no-prefer-dynamic` header * proc-macro crate interactions with all of the above * running of UI tests that include auxiliary files There's no tests for any of the above right now.
This was referenced Apr 7, 2019
bors
added a commit
that referenced
this issue
Apr 9, 2019
Fix ICE in suspicious_else_formatting Fixes #3741
|
I'm still getting a panic in the latest version, however the error message seems to have changed: $ cargo clippy -V
clippy 0.0.212 (d516925e 2019-04-12) |
|
Huh, that should definitely be fixed, I'll have another look, thanks! |
phansch
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to phansch/rust-clippy
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Apr 14, 2019
This was causing two different ICEs in rust-lang#3741. The first was fixed in rust-lang#3925. The second one is fixed with this commit: We just don't `expect` anymore. If the snippet doesn't contain an `else`, we stop emitting the lint because it's not a suspiciously formatted else anyway.
|
Thanks a lot for the fix! It's working with #3960 :-) |
bors
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that referenced
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Apr 14, 2019
Remove `except` in suspicious_else_formatting 96c34e8 contains the fix: This was causing two different ICEs in #3741. The first was fixed in #3925. The second one is fixed with this commit: We just don't `expect` anymore. If the snippet doesn't contain an `else`, we stop emitting the lint because it's not a suspiciously formatted else anyway. Unfortunately I wasn't able to provide a minimal test case, but I think it's fine since it's just ignoring the `None` case now. And ad27e3f cleans up the lint code to use `if_chain`. Fixes #3741 once more.
phansch
added a commit
to phansch/compiletest-rs
that referenced
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Aug 21, 2019
Taken from work on rust-lang/rust-clippy#3741. I think this is a useful test to have because it tests * the `run-pass` header * the `aux-build` header, building auxiliary files * the `no-prefer-dynamic` header * proc-macro crate interactions with all of the above * running of UI tests that include auxiliary files There's no tests for any of the above right now.
phansch
added a commit
to phansch/compiletest-rs
that referenced
this issue
Aug 21, 2019
Taken from work on rust-lang/rust-clippy#3741. I think this is a useful test to have because it tests * the `run-pass` header * the `aux-build` header, building auxiliary files * the `no-prefer-dynamic` header * proc-macro crate interactions with all of the above * running of UI tests that include auxiliary files There's no tests for any of the above right now.
phansch
added a commit
to phansch/compiletest-rs
that referenced
this issue
Aug 21, 2019
Taken from work on rust-lang/rust-clippy#3741. I think this is a useful test to have because it tests * the `run-pass` header * the `aux-build` header, building auxiliary files * the `no-prefer-dynamic` header * proc-macro crate interactions with all of the above * running of UI tests that include auxiliary files There's no tests for any of the above right now.
anelson
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to anelson/tracers
that referenced
this issue
Nov 20, 2019
Now that rust-lang/rust-clippy#3741 has been fixed this should work.
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clippy 0.0.212 (1b89724 2019-01-15)
When using clippy on a project with
#[widget]macro from "relm" crate I get the following panic:Normal
cargo buildworks just fineI've created small project where this crash can be easily reproduced.
Here are repro steps:
Thank you!
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