compiler/rustc_attr_parsing/src/lints.rs

use rustc_errors::{DiagArgValue, LintEmitter};
use rustc_hir::lints::{AttributeLint, AttributeLintKind};
use rustc_hir::{HirId, Target};
use rustc_span::sym;

use crate::session_diagnostics;

pub fn emit_attribute_lint<L: LintEmitter>(lint: &AttributeLint<HirId>, lint_emitter: L) {
    let AttributeLint { id, span, kind } = lint;

    match kind {
        &AttributeLintKind::UnusedDuplicate { this, other, warning } => lint_emitter
            .emit_node_span_lint(
                rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
                *id,
                *span,
                session_diagnostics::UnusedDuplicate { this, other, warning },
            ),
        AttributeLintKind::IllFormedAttributeInput { suggestions } => {
            lint_emitter.emit_node_span_lint(
                rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT,
                *id,
                *span,
                session_diagnostics::IllFormedAttributeInput {
                    num_suggestions: suggestions.len(),
                    suggestions: DiagArgValue::StrListSepByAnd(
                        suggestions.into_iter().map(|s| format!("`{s}`").into()).collect(),
                    ),
                },
            );
        }
        AttributeLintKind::EmptyAttribute { first_span } => lint_emitter.emit_node_span_lint(
            rustc_session::lint::builtin::UNUSED_ATTRIBUTES,
            *id,
            *first_span,
            session_diagnostics::EmptyAttributeList { attr_span: *first_span },
        ),
        &AttributeLintKind::InvalidTarget { name, target, ref applied, only } => lint_emitter
            .emit_node_span_lint(
                // This check is here because `deprecated` had its own lint group and removing this would be a breaking change
                if name == sym::deprecated
                    && ![Target::Closure, Target::Expression, Target::Statement, Target::Arm]
                        .contains(&target)
                {
                    rustc_session::lint::builtin::USELESS_DEPRECATED
                } else {
                    rustc_session::lint::builtin::UNUSED_ATTRIBUTES
                },
                *id,
                *span,
                session_diagnostics::InvalidTargetLint {
                    name,
                    target: target.plural_name(),
                    applied: applied.clone(),
                    only,
                    attr_span: *span,
                },
            ),
    }
}