use rustc::lint::*;
use rustc::ty::TypeVariants;
use syntax::ast::LitKind;
+use syntax::symbol::InternedString;
use utils::paths;
-use utils::{is_expn_of, match_path, match_type, span_lint, walk_ptrs_ty};
+use utils::{is_expn_of, match_def_path, match_type, resolve_node, span_lint, walk_ptrs_ty};
/// **What it does:** Checks for the use of `format!("string literal with no
/// argument")` and `format!("{}", foo)` where `foo` is a string.
/// be replaced by `"foo".to_owned()` if you really need a `String`. The even
/// worse `&format!("foo")` is often encountered in the wild. `format!("{}",
/// foo)` can be replaced by `foo.clone()` if `foo: String` or `foo.to_owned()`
-/// is `foo: &str`.
+/// if `foo: &str`.
///
/// **Known problems:** None.
///
}
}
-impl LateLintPass for Pass {
- fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
+impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
+ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if let Some(span) = is_expn_of(cx, expr.span, "format") {
match expr.node {
// `format!("{}", foo)` expansion
ExprCall(ref fun, ref args) => {
if_let_chain!{[
- let ExprPath(_, ref path) = fun.node,
+ let ExprPath(ref qpath) = fun.node,
args.len() == 2,
- match_path(path, &paths::FMT_ARGUMENTS_NEWV1),
+ match_def_path(cx, resolve_node(cx, qpath, fun.id).def_id(), &paths::FMT_ARGUMENTS_NEWV1),
// ensure the format string is `"{..}"` with only one argument and no text
check_static_str(cx, &args[0]),
// ensure the format argument is `{}` ie. Display with no fancy option
}
}
-/// Checks if the expressions matches
-/// ```rust
-/// { static __STATIC_FMTSTR: &[""] = _; __STATIC_FMTSTR }
-/// ```
-fn check_static_str(cx: &LateContext, expr: &Expr) -> bool {
+/// Returns the slice of format string parts in an `Arguments::new_v1` call.
+/// Public because it's shared with a lint in print.rs.
+pub fn get_argument_fmtstr_parts<'a, 'b>(cx: &LateContext<'a, 'b>, expr: &'a Expr)
+ -> Option<Vec<InternedString>> {
if_let_chain! {[
let ExprBlock(ref block) = expr.node,
block.stmts.len() == 1,
let StmtDecl(ref decl, _) = block.stmts[0].node,
let DeclItem(ref decl) = decl.node,
let Some(NodeItem(decl)) = cx.tcx.map.find(decl.id),
- decl.name.as_str() == "__STATIC_FMTSTR",
+ &*decl.name.as_str() == "__STATIC_FMTSTR",
let ItemStatic(_, _, ref expr) = decl.node,
- let ExprAddrOf(_, ref expr) = expr.node, // &[""]
- let ExprVec(ref expr) = expr.node,
- expr.len() == 1,
- let ExprLit(ref lit) = expr[0].node,
- let LitKind::Str(ref lit, _) = lit.node,
- lit.is_empty()
+ let ExprAddrOf(_, ref expr) = expr.node, // &["…", "…", …]
+ let ExprArray(ref exprs) = expr.node,
], {
- return true;
+ let mut result = Vec::new();
+ for expr in exprs {
+ if let ExprLit(ref lit) = expr.node {
+ if let LitKind::Str(ref lit, _) = lit.node {
+ result.push(lit.as_str());
+ }
+ }
+ }
+ return Some(result);
}}
+ None
+}
- false
+/// Checks if the expressions matches
+/// ```rust
+/// { static __STATIC_FMTSTR: … = &["…", "…", …]; __STATIC_FMTSTR }
+/// ```
+fn check_static_str(cx: &LateContext, expr: &Expr) -> bool {
+ if let Some(expr) = get_argument_fmtstr_parts(cx, expr) {
+ expr.len() == 1 && expr[0].is_empty()
+ } else {
+ false
+ }
}
/// Checks if the expressions matches
arms[0].pats.len() == 1,
let PatKind::Tuple(ref pat, None) = arms[0].pats[0].node,
pat.len() == 1,
- let ExprVec(ref exprs) = arms[0].body.node,
+ let ExprArray(ref exprs) = arms[0].body.node,
exprs.len() == 1,
let ExprCall(_, ref args) = exprs[0].node,
args.len() == 2,
- let ExprPath(None, ref path) = args[1].node,
- match_path(path, &paths::DISPLAY_FMT_METHOD)
+ let ExprPath(ref qpath) = args[1].node,
+ match_def_path(cx, resolve_node(cx, qpath, args[1].id).def_id(), &paths::DISPLAY_FMT_METHOD),
], {
- let ty = walk_ptrs_ty(cx.tcx.pat_ty(&pat[0]));
+ let ty = walk_ptrs_ty(cx.tcx.tables().pat_ty(&pat[0]));
return ty.sty == TypeVariants::TyStr || match_type(cx, ty, &paths::STRING);
}}