use crate::utils::paths;
use crate::utils::{
- is_expn_of, last_path_segment, match_def_path, match_function_call, match_type, snippet, span_lint_and_then,
- walk_ptrs_ty,
+ is_expn_of, is_type_diagnostic_item, last_path_segment, match_def_path, match_function_call, snippet, snippet_opt,
+ span_lint_and_then,
};
use if_chain::if_chain;
+use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, MatchSource, PatKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
-use syntax::ast::LitKind;
+use rustc_span::sym;
declare_clippy_lint! {
/// **What it does:** Checks for the use of `format!("string literal with no
///
/// **Examples:**
/// ```rust
- /// # let foo = "foo";
- /// format!("foo");
+ ///
+ /// // Bad
+ /// let foo = "foo";
/// format!("{}", foo);
+ ///
+ /// // Good
+ /// foo.to_owned();
/// ```
pub USELESS_FORMAT,
complexity,
declare_lint_pass!(UselessFormat => [USELESS_FORMAT]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessFormat {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
+impl<'tcx> LateLintPass<'tcx> for UselessFormat {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
let span = match is_expn_of(expr.span, "format") {
Some(s) if !s.from_expansion() => s,
_ => return,
sugg.push(';');
}
- span_lint_and_then(cx, USELESS_FORMAT, span, "useless use of `format!`", |db| {
- db.span_suggestion(
+ span_lint_and_then(cx, USELESS_FORMAT, span, "useless use of `format!`", |diag| {
+ diag.span_suggestion(
to_replace,
help,
sugg,
});
}
-fn on_argumentv1_new<'a, 'tcx>(
- cx: &LateContext<'a, 'tcx>,
- expr: &'tcx Expr<'_>,
- arms: &'tcx [Arm<'_>],
-) -> Option<String> {
+fn on_argumentv1_new<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) -> Option<String> {
if_chain! {
if let ExprKind::AddrOf(BorrowKind::Ref, _, ref format_args) = expr.kind;
if let ExprKind::Array(ref elems) = arms[0].body.kind;
// matches `core::fmt::Display::fmt`
if args.len() == 2;
if let ExprKind::Path(ref qpath) = args[1].kind;
- if let Some(did) = cx.tables.qpath_res(qpath, args[1].hir_id).opt_def_id();
+ if let Some(did) = cx.qpath_res(qpath, args[1].hir_id).opt_def_id();
if match_def_path(cx, did, &paths::DISPLAY_FMT_METHOD);
// check `(arg0,)` in match block
if let PatKind::Tuple(ref pats, None) = arms[0].pat.kind;
if pats.len() == 1;
then {
- let ty = walk_ptrs_ty(cx.tables.pat_ty(&pats[0]));
- if ty.kind != rustc::ty::Str && !match_type(cx, ty, &paths::STRING) {
+ let ty = cx.typeck_results().pat_ty(&pats[0]).peel_refs();
+ if *ty.kind() != rustc_middle::ty::Str && !is_type_diagnostic_item(cx, ty, sym::string_type) {
return None;
}
if let ExprKind::Lit(ref lit) = format_args.kind {
}
} else {
let snip = snippet(cx, format_args.span, "<arg>");
- if let ExprKind::MethodCall(ref path, _, _) = format_args.kind {
+ if let ExprKind::MethodCall(ref path, _, _, _) = format_args.kind {
if path.ident.name == sym!(to_string) {
return Some(format!("{}", snip));
}
None
}
-fn on_new_v1<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
+fn on_new_v1<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
if_chain! {
if let Some(args) = match_function_call(cx, expr, &paths::FMT_ARGUMENTS_NEW_V1);
if args.len() == 2;
then {
// `format!("foo")` expansion contains `match () { () => [], }`
if tup.is_empty() {
- return Some(format!("{:?}.to_string()", s.as_str()));
+ if let Some(s_src) = snippet_opt(cx, lit.span) {
+ // Simulate macro expansion, converting {{ and }} to { and }.
+ let s_expand = s_src.replace("{{", "{").replace("}}", "}");
+ return Some(format!("{}.to_string()", s_expand))
+ }
} else if s.as_str().is_empty() {
return on_argumentv1_new(cx, &tup[0], arms);
}
None
}
-fn on_new_v1_fmt<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
+fn on_new_v1_fmt<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<String> {
if_chain! {
if let Some(args) = match_function_call(cx, expr, &paths::FMT_ARGUMENTS_NEW_V1_FORMATTED);
if args.len() == 3;
if exprs.len() == 1;
// struct `core::fmt::rt::v1::Argument`
if let ExprKind::Struct(_, ref fields, _) = exprs[0].kind;
- if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym!(format));
+ if let Some(format_field) = fields.iter().find(|f| f.ident.name == sym::format);
// struct `core::fmt::rt::v1::FormatSpec`
if let ExprKind::Struct(_, ref fields, _) = format_field.expr.kind;
- if let Some(precision_field) = fields.iter().find(|f| f.ident.name == sym!(precision));
+ if let Some(precision_field) = fields.iter().find(|f| f.ident.name == sym::precision);
if let ExprKind::Path(ref precision_path) = precision_field.expr.kind;
- if last_path_segment(precision_path).ident.name == sym!(Implied);
- if let Some(width_field) = fields.iter().find(|f| f.ident.name == sym!(width));
+ if last_path_segment(precision_path).ident.name == sym::Implied;
+ if let Some(width_field) = fields.iter().find(|f| f.ident.name == sym::width);
if let ExprKind::Path(ref width_qpath) = width_field.expr.kind;
- if last_path_segment(width_qpath).ident.name == sym!(Implied);
+ if last_path_segment(width_qpath).ident.name == sym::Implied;
then {
return true;
}