SemverQuery(
id: "enum_struct_variant_field_added",
human_readable_name: "pub enum struct variant field added",
description: "An enum's exhaustive struct variant has a new field.",
required_update: Major,
lint_level: Deny,
reference_link: Some("https://doc.rust-lang.org/reference/attributes/type_system.html#the-non_exhaustive-attribute"),
query: r#"
{
CrateDiff {
current {
item {
... on Enum {
visibility_limit @filter(op: "=", value: ["$public"])
enum_name: name @output
importable_path {
path @output @tag
public_api @filter(op: "=", value: ["$true"])
}
variant {
... on StructVariant {
# If the variant is now marked `#[non_exhaustive]`,
# that's already a breaking change that has its own rule.
# Don't also report new field additions, since the programmer has
# clearly stated that they don't consider it exhaustive anymore.
attrs @filter(op: "not_contains", value: ["$non_exhaustive"])
# If the variant is newly marked `#[doc(hidden)]`,
# that's already a breaking change with its own rule.
# Don't report new field additions, since the programmer has
# clearly stated they don't consider it public API anymore.
public_api_eligible @filter(op: "=", value: ["$true"])
variant_name: name @output @tag
field {
field_name: name @output @tag
span_: span @optional {
filename @output
begin_line @output
end_line @output
}
}
}
}
}
}
}
baseline {
item {
... on Enum {
visibility_limit @filter(op: "=", value: ["$public"])
importable_path {
path @filter(op: "=", value: ["%path"])
public_api @filter(op: "=", value: ["$true"])
}
variant {
... on StructVariant {
name @filter(op: "=", value: ["%variant_name"])
attrs @filter(op: "not_contains", value: ["$non_exhaustive"])
public_api_eligible @filter(op: "=", value: ["$true"])
field @fold @transform(op: "count") @filter(op: "=", value: ["$zero"]) {
name @filter(op: "=", value: ["%field_name"])
}
field @fold {
baseline_field_names: name @output
}
}
}
}
}
}
}
}"#,
arguments: {
"public": "public",
"true": true,
"zero": 0,
"non_exhaustive": "#[non_exhaustive]",
},
error_message: "An enum's exhaustive struct variant has a new field, which has to be included when constructing or matching on this variant.",
per_result_error_template: Some("field {{field_name}} of variant {{enum_name}}::{{variant_name}} in {{span_filename}}:{{span_begin_line}}"),
witness: (
hint_template: r#"match value {
{{ join "::" path }}::{{ variant_name }} { {{ join ", " baseline_field_names }} } => (),
_ => (),
}"#,
)
)