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Auto merge of #5279 - DevinR528:macro-use-sugg, r=flip1995
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Macro use sugg

changelog: Add auto applicable suggstion to macro_use_imports

fixes #5275

<s>Where exactly is the `wildcard_imports_helper` I haven't been able to import anything ex.
`use lazy_static;` or something like for that I get version/compiler conflicts?</s>
Found it.

Should we also check for `#[macro_use] extern crate`, although this is still depended on for stuff like `rustc_private`?
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bors committed Jun 9, 2020
2 parents ff0993c + e521a4e commit f065d4b
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Showing 6 changed files with 360 additions and 28 deletions.
2 changes: 1 addition & 1 deletion clippy_lints/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1062,7 +1062,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_early_pass(|| box option_env_unwrap::OptionEnvUnwrap);
let warn_on_all_wildcard_imports = conf.warn_on_all_wildcard_imports;
store.register_late_pass(move || box wildcard_imports::WildcardImports::new(warn_on_all_wildcard_imports));
store.register_early_pass(|| box macro_use::MacroUseImports);
store.register_late_pass(|| box verbose_file_reads::VerboseFileReads);
store.register_late_pass(|| box redundant_pub_crate::RedundantPubCrate::default());
store.register_late_pass(|| box unnamed_address::UnnamedAddress);
Expand All @@ -1080,6 +1079,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
single_char_binding_names_threshold,
});
store.register_early_pass(|| box unnested_or_patterns::UnnestedOrPatterns);
store.register_late_pass(|| box macro_use::MacroUseImports::default());

store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
LintId::of(&arithmetic::FLOAT_ARITHMETIC),
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213 changes: 196 additions & 17 deletions clippy_lints/src/macro_use.rs
Original file line number Diff line number Diff line change
@@ -1,18 +1,21 @@
use crate::utils::{snippet, span_lint_and_sugg};
use crate::utils::{in_macro, snippet, span_lint_and_sugg};
use hir::def::{DefKind, Res};
use if_chain::if_chain;
use rustc_ast::ast;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_errors::Applicability;
use rustc_lint::{EarlyContext, EarlyLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::edition::Edition;
use rustc_hir as hir;
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::{edition::Edition, Span};

declare_clippy_lint! {
/// **What it does:** Checks for `#[macro_use] use...`.
///
/// **Why is this bad?** Since the Rust 2018 edition you can import
/// macro's directly, this is considered idiomatic.
///
/// **Known problems:** This lint does not generate an auto-applicable suggestion.
/// **Known problems:** None.
///
/// **Example:**
/// ```rust
Expand All @@ -24,29 +27,205 @@ declare_clippy_lint! {
"#[macro_use] is no longer needed"
}

declare_lint_pass!(MacroUseImports => [MACRO_USE_IMPORTS]);
const BRACKETS: &[char] = &['<', '>'];

impl EarlyLintPass for MacroUseImports {
fn check_item(&mut self, ecx: &EarlyContext<'_>, item: &ast::Item) {
#[derive(Clone, Debug, PartialEq, Eq)]
struct PathAndSpan {
path: String,
span: Span,
}

/// `MacroRefData` includes the name of the macro
/// and the path from `SourceMap::span_to_filename`.
#[derive(Debug, Clone)]
pub struct MacroRefData {
name: String,
path: String,
}

impl MacroRefData {
pub fn new(name: String, callee: Span, cx: &LateContext<'_, '_>) -> Self {
let mut path = cx.sess().source_map().span_to_filename(callee).to_string();

// std lib paths are <::std::module::file type>
// so remove brackets, space and type.
if path.contains('<') {
path = path.replace(BRACKETS, "");
}
if path.contains(' ') {
path = path.split(' ').next().unwrap().to_string();
}
Self { name, path }
}
}

#[derive(Default)]
#[allow(clippy::module_name_repetitions)]
pub struct MacroUseImports {
/// the actual import path used and the span of the attribute above it.
imports: Vec<(String, Span)>,
/// the span of the macro reference, kept to ensure only one reference is used per macro call.
collected: FxHashSet<Span>,
mac_refs: Vec<MacroRefData>,
}

impl_lint_pass!(MacroUseImports => [MACRO_USE_IMPORTS]);

impl MacroUseImports {
fn push_unique_macro(&mut self, cx: &LateContext<'_, '_>, span: Span) {
let call_site = span.source_callsite();
let name = snippet(cx, cx.sess().source_map().span_until_char(call_site, '!'), "_");
if let Some(callee) = span.source_callee() {
if !self.collected.contains(&call_site) {
let name = if name.contains("::") {
name.split("::").last().unwrap().to_string()
} else {
name.to_string()
};

self.mac_refs.push(MacroRefData::new(name, callee.def_site, cx));
self.collected.insert(call_site);
}
}
}

fn push_unique_macro_pat_ty(&mut self, cx: &LateContext<'_, '_>, span: Span) {
let call_site = span.source_callsite();
let name = snippet(cx, cx.sess().source_map().span_until_char(call_site, '!'), "_");
if let Some(callee) = span.source_callee() {
if !self.collected.contains(&call_site) {
self.mac_refs
.push(MacroRefData::new(name.to_string(), callee.def_site, cx));
self.collected.insert(call_site);
}
}
}
}

impl<'l, 'txc> LateLintPass<'l, 'txc> for MacroUseImports {
fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item<'_>) {
if_chain! {
if ecx.sess.opts.edition == Edition::Edition2018;
if let ast::ItemKind::Use(use_tree) = &item.kind;
if cx.sess().opts.edition == Edition::Edition2018;
if let hir::ItemKind::Use(path, _kind) = &item.kind;
if let Some(mac_attr) = item
.attrs
.iter()
.find(|attr| attr.ident().map(|s| s.to_string()) == Some("macro_use".to_string()));
if let Res::Def(DefKind::Mod, id) = path.res;
then {
let msg = "`macro_use` attributes are no longer needed in the Rust 2018 edition";
let help = format!("use {}::<macro name>", snippet(ecx, use_tree.span, "_"));
for kid in cx.tcx.item_children(id).iter() {
if let Res::Def(DefKind::Macro(_mac_type), mac_id) = kid.res {
let span = mac_attr.span;
let def_path = cx.tcx.def_path_str(mac_id);
self.imports.push((def_path, span));
}
}
} else {
if in_macro(item.span) {
self.push_unique_macro_pat_ty(cx, item.span);
}
}
}
}
fn check_attribute(&mut self, cx: &LateContext<'_, '_>, attr: &ast::Attribute) {
if in_macro(attr.span) {
self.push_unique_macro(cx, attr.span);
}
}
fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) {
if in_macro(expr.span) {
self.push_unique_macro(cx, expr.span);
}
}
fn check_stmt(&mut self, cx: &LateContext<'_, '_>, stmt: &hir::Stmt<'_>) {
if in_macro(stmt.span) {
self.push_unique_macro(cx, stmt.span);
}
}
fn check_pat(&mut self, cx: &LateContext<'_, '_>, pat: &hir::Pat<'_>) {
if in_macro(pat.span) {
self.push_unique_macro_pat_ty(cx, pat.span);
}
}
fn check_ty(&mut self, cx: &LateContext<'_, '_>, ty: &hir::Ty<'_>) {
if in_macro(ty.span) {
self.push_unique_macro_pat_ty(cx, ty.span);
}
}
#[allow(clippy::too_many_lines)]
fn check_crate_post(&mut self, cx: &LateContext<'_, '_>, _krate: &hir::Crate<'_>) {
let mut used = FxHashMap::default();
let mut check_dup = vec![];
for (import, span) in &self.imports {
let found_idx = self.mac_refs.iter().position(|mac| import.ends_with(&mac.name));

if let Some(idx) = found_idx {
let _ = self.mac_refs.remove(idx);
let seg = import.split("::").collect::<Vec<_>>();

match seg.as_slice() {
// an empty path is impossible
// a path should always consist of 2 or more segments
[] | [_] => return,
[root, item] => {
if !check_dup.contains(&(*item).to_string()) {
used.entry(((*root).to_string(), span))
.or_insert_with(Vec::new)
.push((*item).to_string());
check_dup.push((*item).to_string());
}
},
[root, rest @ ..] => {
if rest.iter().all(|item| !check_dup.contains(&(*item).to_string())) {
let filtered = rest
.iter()
.filter_map(|item| {
if check_dup.contains(&(*item).to_string()) {
None
} else {
Some((*item).to_string())
}
})
.collect::<Vec<_>>();
used.entry(((*root).to_string(), span))
.or_insert_with(Vec::new)
.push(filtered.join("::"));
check_dup.extend(filtered);
} else {
let rest = rest.to_vec();
used.entry(((*root).to_string(), span))
.or_insert_with(Vec::new)
.push(rest.join("::"));
check_dup.extend(rest.iter().map(ToString::to_string));
}
},
}
}
}

let mut suggestions = vec![];
for ((root, span), path) in used {
if path.len() == 1 {
suggestions.push((span, format!("{}::{}", root, path[0])))
} else {
suggestions.push((span, format!("{}::{{{}}}", root, path.join(", "))))
}
}

// If mac_refs is not empty we have encountered an import we could not handle
// such as `std::prelude::v1::foo` or some other macro that expands to an import.
if self.mac_refs.is_empty() {
for (span, import) in suggestions {
let help = format!("use {};", import);
span_lint_and_sugg(
ecx,
cx,
MACRO_USE_IMPORTS,
mac_attr.span,
msg,
*span,
"`macro_use` attributes are no longer needed in the Rust 2018 edition",
"remove the attribute and import the macro directly, try",
help,
Applicability::HasPlaceholders,
);
Applicability::MaybeIncorrect,
)
}
}
}
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60 changes: 60 additions & 0 deletions tests/ui/auxiliary/macro_use_helper.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,60 @@
extern crate macro_rules;

// STMT
#[macro_export]
macro_rules! pub_macro {
() => {
let _ = "hello Mr. Vonnegut";
};
}

pub mod inner {
pub use super::*;

// RE-EXPORT
// this will stick in `inner` module
pub use macro_rules::foofoo;
pub use macro_rules::try_err;

pub mod nested {
pub use macro_rules::string_add;
}

// ITEM
#[macro_export]
macro_rules! inner_mod_macro {
() => {
#[allow(dead_code)]
pub struct Tardis;
};
}
}

// EXPR
#[macro_export]
macro_rules! function_macro {
() => {
if true {
} else {
}
};
}

// TYPE
#[macro_export]
macro_rules! ty_macro {
() => {
Vec<u8>
};
}

mod extern_exports {
pub(super) mod private_inner {
#[macro_export]
macro_rules! pub_in_private_macro {
($name:ident) => {
let $name = String::from("secrets and lies");
};
}
}
}
43 changes: 43 additions & 0 deletions tests/ui/macro_use_imports.fixed
Original file line number Diff line number Diff line change
@@ -0,0 +1,43 @@
// compile-flags: --edition 2018
// aux-build:macro_rules.rs
// aux-build:macro_use_helper.rs
// run-rustfix
// ignore-32bit

#![allow(unused_imports, unreachable_code, unused_variables, dead_code)]
#![allow(clippy::single_component_path_imports)]
#![warn(clippy::macro_use_imports)]

#[macro_use]
extern crate macro_use_helper as mac;

#[macro_use]
extern crate clippy_mini_macro_test as mini_mac;

mod a {
use mac::{pub_macro, inner_mod_macro, function_macro, ty_macro, pub_in_private_macro};
use mac;
use mini_mac::ClippyMiniMacroTest;
use mini_mac;
use mac::{inner::foofoo, inner::try_err};
use mac::inner;
use mac::inner::nested::string_add;
use mac::inner::nested;

#[derive(ClippyMiniMacroTest)]
struct Test;

fn test() {
pub_macro!();
inner_mod_macro!();
pub_in_private_macro!(_var);
function_macro!();
let v: ty_macro!() = Vec::default();

inner::try_err!();
inner::foofoo!();
nested::string_add!();
}
}

fn main() {}
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