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Description
I've tracked down a few things that are preventing this from happening.
packed_structrequires std by default- There are a few uses of std in
cranelift-codegenandcranelift-codegen-sharedthat can be replaced with core or alloc. thiserrorrequires std, because the Error trait doesn't exist in core or alloc.
The first two are trivial to fix, and I'll create a PR with those changes in a second.
However, there are 11 uses of the Display and Into<result::CodegenError> traits that prevent me from placing thiserror behind a feature gate, and I'm not sure what to do about them.
Here are the 11 things that rely on those traits, as reported by rustc (click to expand)
$ cargo build --no-default-features --features core
Compiling cranelift-codegen v0.51.0 (/home/icydefiance/Documents/code/cranelift/cranelift-codegen)
error[E0599]: no method named `to_string` found for type `verifier::VerifierError` in the current scope
--> cranelift-codegen/src/print_errors.rs:218:36
|
218 | writeln!(w, "; error: {}", err.to_string())?;
| ^^^^^^^^^ method not found in `verifier::VerifierError`
|
::: cranelift-codegen/src/verifier/mod.rs:138:1
|
138 | pub struct VerifierError {
| ------------------------ method `to_string` not found for this
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `to_string`, perhaps you need to implement it:
candidate bytecodealliance/cranelift#1: `alloc::string::ToString`
error[E0599]: no method named `to_string` found for type `result::CodegenError` in the current scope
--> cranelift-codegen/src/print_errors.rs:227:13
|
227 | err.to_string()
| ^^^^^^^^^ method not found in `result::CodegenError`
|
::: cranelift-codegen/src/result.rs:12:1
|
12 | pub enum CodegenError {
| --------------------- method `to_string` not found for this
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `to_string`, perhaps you need to implement it:
candidate bytecodealliance/cranelift#1: `alloc::string::ToString`
error[E0277]: `verifier::VerifierError` doesn't implement `core::fmt::Display`
--> cranelift-codegen/src/verifier/mod.rs:235:33
|
235 | writeln!(f, "- {}", err)?;
| ^^^ `verifier::VerifierError` cannot be formatted with the default formatter
|
= help: the trait `core::fmt::Display` is not implemented for `verifier::VerifierError`
= note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
= note: required because of the requirements on the impl of `core::fmt::Display` for `&verifier::VerifierError`
= note: required by `core::fmt::Display::fmt`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/context.rs:224:30
|
224 | self.verify(fisa)?;
| ^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required by `core::convert::From::from`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/context.rs:244:39
|
244 | self.verify_locations(isa)?;
| ^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required by `core::convert::From::from`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/regalloc/context.rs:111:28
|
111 | return Err(errors.into());
| ^^^^^^^^^^^^^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required because of the requirements on the impl of `core::convert::Into<result::CodegenError>` for `verifier::VerifierErrors`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/regalloc/context.rs:139:28
|
139 | return Err(errors.into());
| ^^^^^^^^^^^^^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required because of the requirements on the impl of `core::convert::Into<result::CodegenError>` for `verifier::VerifierErrors`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/regalloc/context.rs:168:28
|
168 | return Err(errors.into());
| ^^^^^^^^^^^^^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required because of the requirements on the impl of `core::convert::Into<result::CodegenError>` for `verifier::VerifierErrors`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/regalloc/context.rs:196:28
|
196 | return Err(errors.into());
| ^^^^^^^^^^^^^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required because of the requirements on the impl of `core::convert::Into<result::CodegenError>` for `verifier::VerifierErrors`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/regalloc/context.rs:239:28
|
239 | return Err(errors.into());
| ^^^^^^^^^^^^^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required because of the requirements on the impl of `core::convert::Into<result::CodegenError>` for `verifier::VerifierErrors`
error[E0277]: the trait bound `result::CodegenError: core::convert::From<verifier::VerifierErrors>` is not satisfied
--> cranelift-codegen/src/regalloc/context.rs:248:17
|
248 | Err(errors.into())
| ^^^^^^^^^^^^^ the trait `core::convert::From<verifier::VerifierErrors>` is not implemented for `result::CodegenError`
|
= note: required because of the requirements on the impl of `core::convert::Into<result::CodegenError>` for `verifier::VerifierErrors`
error: aborting due to 11 previous errors
Some errors have detailed explanations: E0277, E0599.
For more information about an error, try `rustc --explain E0277`.
error: could not compile `cranelift-codegen`.
To learn more, run the command again with --verbose.
Additional info:
- The author of
thiserrordoesn't want to add a feature-gate for just the Error trait, but it's possible to provide another implementation of Display (and presumably Into). Option toimpl Errorunder feature flag dtolnay/thiserror#43 - There was some discussion of moving Error to alloc, and a PR was even created to do so, but it was closed because RFC 2504 will add backtrace functionality that requires std.