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Auto merge of #12283 - nyurik:ref-format-args, r=xFrednet

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Minor refactor format-args

* Move all linting logic into a single format implementations struct

This should help with the future format-args improvements.

**NOTE TO REVIEWERS**:  use "hide whitespace" in the github diff -- most of the code has shifted, but relatively low number of lines actually modified.

Followig up from #12274

r? `@xFrednet`

---

changelog: none
This commit is contained in:
bors 2024-02-12 22:31:50 +00:00
commit 4350678ec7
1 changed files with 256 additions and 247 deletions
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141
clippy_lints/src/format_args.rs
View File

@ -4,7 +4,7 @@ use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
use clippy_utils::is_diag_trait_item;
use clippy_utils::macros::{
find_format_arg_expr, find_format_args, format_arg_removal_span, format_placeholder_format_span, is_assert_macro,
is_format_macro, is_panic, root_macro_call, root_macro_call_first_node, FormatParamUsage,
is_format_macro, is_panic, root_macro_call, root_macro_call_first_node, FormatParamUsage, MacroCall,
};
use clippy_utils::source::snippet_opt;
use clippy_utils::ty::{implements_trait, is_type_lang_item};
@ -20,7 +20,6 @@ use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::ty::adjustment::{Adjust, Adjustment};
use rustc_middle::ty::Ty;
use rustc_session::impl_lint_pass;
use rustc_span::def_id::DefId;
use rustc_span::edition::Edition::Edition2021;
use rustc_span::{sym, Span, Symbol};
@ -189,32 +188,18 @@ impl<'tcx> LateLintPass<'tcx> for FormatArgs {
&& is_format_macro(cx, macro_call.def_id)
&& let Some(format_args) = find_format_args(cx, expr, macro_call.expn)
{
for piece in &format_args.template {
if let FormatArgsPiece::Placeholder(placeholder) = piece
&& let Ok(index) = placeholder.argument.index
&& let Some(arg) = format_args.arguments.all_args().get(index)
{
let arg_expr = find_format_arg_expr(expr, arg);
let linter = FormatArgsExpr {
cx,
expr,
macro_call: &macro_call,
format_args: &format_args,
ignore_mixed: self.ignore_mixed,
};
check_unused_format_specifier(cx, placeholder, arg_expr);
if placeholder.format_trait != FormatTrait::Display
|| placeholder.format_options != FormatOptions::default()
|| is_aliased(&format_args, index)
{
continue;
}
if let Ok(arg_hir_expr) = arg_expr {
let name = cx.tcx.item_name(macro_call.def_id);
check_format_in_format_args(cx, macro_call.span, name, arg_hir_expr);
check_to_string_in_format_args(cx, name, arg_hir_expr);
}
}
}
linter.check_templates();
if self.msrv.meets(msrvs::FORMAT_ARGS_CAPTURE) {
check_uninlined_args(cx, &format_args, macro_call.span, macro_call.def_id, self.ignore_mixed);
linter.check_uninlined_args();
}
}
}
@ -222,15 +207,47 @@ impl<'tcx> LateLintPass<'tcx> for FormatArgs {
extract_msrv_attr!(LateContext);
}
struct FormatArgsExpr<'a, 'tcx> {
cx: &'a LateContext<'tcx>,
expr: &'tcx Expr<'tcx>,
macro_call: &'a MacroCall,
format_args: &'a rustc_ast::FormatArgs,
ignore_mixed: bool,
}
impl<'a, 'tcx> FormatArgsExpr<'a, 'tcx> {
fn check_templates(&self) {
for piece in &self.format_args.template {
if let FormatArgsPiece::Placeholder(placeholder) = piece
&& let Ok(index) = placeholder.argument.index
&& let Some(arg) = self.format_args.arguments.all_args().get(index)
{
let arg_expr = find_format_arg_expr(self.expr, arg);
self.check_unused_format_specifier(placeholder, arg_expr);
if let Ok(arg_expr) = arg_expr
&& placeholder.format_trait == FormatTrait::Display
&& placeholder.format_options == FormatOptions::default()
&& !self.is_aliased(index)
{
let name = self.cx.tcx.item_name(self.macro_call.def_id);
self.check_format_in_format_args(name, arg_expr);
self.check_to_string_in_format_args(name, arg_expr);
}
}
}
}
fn check_unused_format_specifier(
cx: &LateContext<'_>,
&self,
placeholder: &FormatPlaceholder,
arg_expr: Result<&Expr<'_>, &rustc_ast::Expr>,
) {
let ty_or_ast_expr = arg_expr.map(|expr| cx.typeck_results().expr_ty(expr).peel_refs());
let ty_or_ast_expr = arg_expr.map(|expr| self.cx.typeck_results().expr_ty(expr).peel_refs());
let is_format_args = match ty_or_ast_expr {
Ok(ty) => is_type_lang_item(cx, ty, LangItem::FormatArguments),
Ok(ty) => is_type_lang_item(self.cx, ty, LangItem::FormatArguments),
Err(expr) => matches!(expr.peel_parens_and_refs().kind, rustc_ast::ExprKind::FormatArgs(_)),
};
@ -246,7 +263,7 @@ fn check_unused_format_specifier(
&& *options != FormatOptions::default()
{
span_lint_and_then(
cx,
self.cx,
UNUSED_FORMAT_SPECS,
placeholder_span,
"format specifiers have no effect on `format_args!()`",
@ -255,10 +272,10 @@ fn check_unused_format_specifier(
let message = format!("for the {spec} to apply consider using `format!()`");
if let Some(mac_call) = root_macro_call(arg_span)
&& cx.tcx.is_diagnostic_item(sym::format_args_macro, mac_call.def_id)
&& self.cx.tcx.is_diagnostic_item(sym::format_args_macro, mac_call.def_id)
{
diag.span_suggestion(
cx.sess().source_map().span_until_char(mac_call.span, '!'),
self.cx.sess().source_map().span_until_char(mac_call.span, '!'),
message,
"format",
Applicability::MaybeIncorrect,
@ -289,17 +306,13 @@ fn check_unused_format_specifier(
}
}
fn check_uninlined_args(
cx: &LateContext<'_>,
args: &rustc_ast::FormatArgs,
call_site: Span,
def_id: DefId,
ignore_mixed: bool,
) {
if args.span.from_expansion() {
fn check_uninlined_args(&self) {
if self.format_args.span.from_expansion() {
return;
}
if call_site.edition() < Edition2021 && (is_panic(cx, def_id) || is_assert_macro(cx, def_id)) {
if self.macro_call.span.edition() < Edition2021
&& (is_panic(self.cx, self.macro_call.def_id) || is_assert_macro(self.cx, self.macro_call.def_id))
{
// panic!, assert!, and debug_assert! before 2021 edition considers a single string argument as
// non-format
return;
@ -311,8 +324,8 @@ fn check_uninlined_args(
// we cannot remove any other arguments in the format string,
// because the index numbers might be wrong after inlining.
// Example of an un-inlinable format: print!("{}{1}", foo, 2)
for (pos, usage) in format_arg_positions(args) {
if !check_one_arg(args, pos, usage, &mut fixes, ignore_mixed) {
for (pos, usage) in self.format_arg_positions() {
if !self.check_one_arg(pos, usage, &mut fixes) {
return;
}
}
@ -323,16 +336,18 @@ fn check_uninlined_args(
// multiline span display suggestion is sometimes broken: https://github.com/rust-lang/rust/pull/102729#discussion_r988704308
// in those cases, make the code suggestion hidden
let multiline_fix = fixes.iter().any(|(span, _)| cx.sess().source_map().is_multiline(*span));
let multiline_fix = fixes
.iter()
.any(|(span, _)| self.cx.sess().source_map().is_multiline(*span));
// Suggest removing each argument only once, for example in `format!("{0} {0}", arg)`.
fixes.sort_unstable_by_key(|(span, _)| *span);
fixes.dedup_by_key(|(span, _)| *span);
span_lint_and_then(
cx,
self.cx,
UNINLINED_FORMAT_ARGS,
call_site,
self.macro_call.span,
"variables can be used directly in the `format!` string",
|diag| {
diag.multipart_suggestion_with_style(
@ -345,21 +360,15 @@ fn check_uninlined_args(
);
}
fn check_one_arg(
args: &rustc_ast::FormatArgs,
pos: &FormatArgPosition,
usage: FormatParamUsage,
fixes: &mut Vec<(Span, String)>,
ignore_mixed: bool,
) -> bool {
fn check_one_arg(&self, pos: &FormatArgPosition, usage: FormatParamUsage, fixes: &mut Vec<(Span, String)>) -> bool {
let index = pos.index.unwrap();
let arg = &args.arguments.all_args()[index];
let arg = &self.format_args.arguments.all_args()[index];
if !matches!(arg.kind, FormatArgumentKind::Captured(_))
&& let rustc_ast::ExprKind::Path(None, path) = &arg.expr.kind
&& let [segment] = path.segments.as_slice()
&& segment.args.is_none()
&& let Some(arg_span) = format_arg_removal_span(args, index)
&& let Some(arg_span) = format_arg_removal_span(self.format_args, index)
&& let Some(pos_span) = pos.span
{
let replacement = match usage {
@ -375,23 +384,23 @@ fn check_one_arg(
// * if we can't inline a numbered argument, e.g. `print!("{0} ...", foo.bar, ...)`
// * if allow_mixed_uninlined_format_args is false and this arg hasn't been inlined already
pos.kind != FormatArgPositionKind::Number
&& (!ignore_mixed || matches!(arg.kind, FormatArgumentKind::Captured(_)))
&& (!self.ignore_mixed || matches!(arg.kind, FormatArgumentKind::Captured(_)))
}
}
fn check_format_in_format_args(cx: &LateContext<'_>, call_site: Span, name: Symbol, arg: &Expr<'_>) {
fn check_format_in_format_args(&self, name: Symbol, arg: &Expr<'_>) {
let expn_data = arg.span.ctxt().outer_expn_data();
if expn_data.call_site.from_expansion() {
return;
}
let Some(mac_id) = expn_data.macro_def_id else { return };
if !cx.tcx.is_diagnostic_item(sym::format_macro, mac_id) {
if !self.cx.tcx.is_diagnostic_item(sym::format_macro, mac_id) {
return;
}
span_lint_and_then(
cx,
self.cx,
FORMAT_IN_FORMAT_ARGS,
call_site,
self.macro_call.span,
&format!("`format!` in `{name}!` args"),
|diag| {
diag.help(format!(
@ -402,7 +411,8 @@ fn check_format_in_format_args(cx: &LateContext<'_>, call_site: Span, name: Symb
);
}
fn check_to_string_in_format_args(cx: &LateContext<'_>, name: Symbol, value: &Expr<'_>) {
fn check_to_string_in_format_args(&self, name: Symbol, value: &Expr<'_>) {
let cx = self.cx;
if !value.span.from_expansion()
&& let ExprKind::MethodCall(_, receiver, [], to_string_span) = value.kind
&& let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(value.hir_id)
@ -444,10 +454,8 @@ fn check_to_string_in_format_args(cx: &LateContext<'_>, name: Symbol, value: &Ex
}
}
fn format_arg_positions(
format_args: &rustc_ast::FormatArgs,
) -> impl Iterator<Item = (&FormatArgPosition, FormatParamUsage)> {
format_args.template.iter().flat_map(|piece| match piece {
fn format_arg_positions(&self) -> impl Iterator<Item = (&FormatArgPosition, FormatParamUsage)> {
self.format_args.template.iter().flat_map(|piece| match piece {
FormatArgsPiece::Placeholder(placeholder) => {
let mut positions = ArrayVec::<_, 3>::new();
@ -466,12 +474,13 @@ fn format_arg_positions(
}
/// Returns true if the format argument at `index` is referred to by multiple format params
fn is_aliased(format_args: &rustc_ast::FormatArgs, index: usize) -> bool {
format_arg_positions(format_args)
fn is_aliased(&self, index: usize) -> bool {
self.format_arg_positions()
.filter(|(position, _)| position.index == Ok(index))
.at_most_one()
.is_err()
}
}
fn count_needed_derefs<'tcx, I>(mut ty: Ty<'tcx>, mut iter: I) -> (usize, Ty<'tcx>)
where