rust/src/attrs.rs
2015-11-19 15:51:30 +01:00

108 lines
3.0 KiB
Rust

//! checks for attributes
use rustc::lint::*;
use rustc_front::hir::*;
use reexport::*;
use syntax::codemap::Span;
use syntax::attr::*;
use syntax::ast::{Attribute, MetaList, MetaWord};
use utils::{in_macro, match_path, span_lint};
declare_lint! { pub INLINE_ALWAYS, Warn,
"`#[inline(always)]` is a bad idea in most cases" }
#[derive(Copy,Clone)]
pub struct AttrPass;
impl LintPass for AttrPass {
fn get_lints(&self) -> LintArray {
lint_array!(INLINE_ALWAYS)
}
}
impl LateLintPass for AttrPass {
fn check_item(&mut self, cx: &LateContext, item: &Item) {
if is_relevant_item(item) {
check_attrs(cx, item.span, &item.name, &item.attrs)
}
}
fn check_impl_item(&mut self, cx: &LateContext, item: &ImplItem) {
if is_relevant_impl(item) {
check_attrs(cx, item.span, &item.name, &item.attrs)
}
}
fn check_trait_item(&mut self, cx: &LateContext, item: &TraitItem) {
if is_relevant_trait(item) {
check_attrs(cx, item.span, &item.name, &item.attrs)
}
}
}
fn is_relevant_item(item: &Item) -> bool {
if let &ItemFn(_, _, _, _, _, ref block) = &item.node {
is_relevant_block(block)
} else { false }
}
fn is_relevant_impl(item: &ImplItem) -> bool {
match item.node {
ImplItemKind::Method(_, ref block) => is_relevant_block(block),
_ => false
}
}
fn is_relevant_trait(item: &TraitItem) -> bool {
match item.node {
MethodTraitItem(_, None) => true,
MethodTraitItem(_, Some(ref block)) => is_relevant_block(block),
_ => false
}
}
fn is_relevant_block(block: &Block) -> bool {
for stmt in &block.stmts {
match stmt.node {
StmtDecl(_, _) => return true,
StmtExpr(ref expr, _) | StmtSemi(ref expr, _) => {
return is_relevant_expr(expr);
}
}
}
block.expr.as_ref().map_or(false, |e| is_relevant_expr(e))
}
fn is_relevant_expr(expr: &Expr) -> bool {
match expr.node {
ExprBlock(ref block) => is_relevant_block(block),
ExprRet(Some(ref e)) => is_relevant_expr(e),
ExprRet(None) | ExprBreak(_) => false,
ExprCall(ref path_expr, _) => {
if let ExprPath(_, ref path) = path_expr.node {
!match_path(path, &["std", "rt", "begin_unwind"])
} else { true }
}
_ => true
}
}
fn check_attrs(cx: &LateContext, span: Span, name: &Name,
attrs: &[Attribute]) {
if in_macro(cx, span) { return; }
for attr in attrs {
if let MetaList(ref inline, ref values) = attr.node.value.node {
if values.len() != 1 || inline != &"inline" { continue; }
if let MetaWord(ref always) = values[0].node {
if always != &"always" { continue; }
span_lint(cx, INLINE_ALWAYS, attr.span, &format!(
"you have declared `#[inline(always)]` on `{}`. This \
is usually a bad idea",
name));
}
}
}
}