collected all the imports and names

how to compare macro to import path

add more imports to test

7 files changed, 281 insertions, 73 deletions

diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index cd258c7b506..89f55986f63 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -60,6 +60,7 @@ extern crate rustc_trait_selection;
 #[allow(unused_extern_crates)]
 extern crate rustc_typeck;
 
+use rustc::session::Session;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_lint::LintId;
 use rustc_session::Session;
@@ -1060,9 +1061,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     let max_struct_bools = conf.max_struct_bools;
     store.register_early_pass(move || box excessive_bools::ExcessiveBools::new(max_struct_bools, max_fn_params_bools));
     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 wildcard_imports::WildcardImports);
     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);
@@ -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),
diff --git a/clippy_lints/src/macro_use.rs b/clippy_lints/src/macro_use.rs
index cf526409374..4c89647a574 100644
--- a/clippy_lints/src/macro_use.rs
+++ b/clippy_lints/src/macro_use.rs
@@ -1,10 +1,12 @@
-use crate::utils::{snippet, span_lint_and_sugg, in_macro};
+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::FxHashSet;
+use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::Applicability;
-use rustc_lint::{EarlyContext, EarlyLintPass};
-use rustc_session::{impl_lint_pass, declare_tool_lint};
+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! {
@@ -20,82 +22,226 @@ declare_clippy_lint! {
     /// #[macro_use]
     /// use lazy_static;
     /// ```
-    pub MACRO_USE_IMPORT,
+    pub MACRO_USE_IMPORTS,
     pedantic,
     "#[macro_use] is no longer needed"
 }
 
-#[derive(Default)]
-pub struct MacroUseImport {
-    collected: FxHashSet<Span>,
+const BRACKETS: &[char] = &['<', '>'];
+
+/// 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_lint_pass!(MacroUseImport => [MACRO_USE_IMPORT]);
+impl MacroRefData {
+    pub fn new(name: String, span: Span, ecx: &LateContext<'_, '_>) -> Self {
+        let mut path = ecx.sess().source_map().span_to_filename(span).to_string();
 
-impl EarlyLintPass for MacroUseImport {
+        // std lib paths are <::std::module::file type>
+        // so remove brackets and space
+        if path.contains('<') {
+            path = path.replace(BRACKETS, "");
+        }
+        if path.contains(' ') {
+            path = path.split(' ').next().unwrap().to_string();
+        }
+        Self {
+            name: name.to_string(),
+            path,
+        }
+    }
+}
 
-    fn check_item(&mut self, ecx: &EarlyContext<'_>, item: &ast::Item) {
+#[derive(Default)]
+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 and the `MacroRefData`
+    /// for the use of the macro.
+    /// TODO make this FxHashSet<Span> to guard against inserting already found macros
+    collected: FxHashMap<Span, MacroRefData>,
+    mac_refs: Vec<(Span, MacroRefData)>,
+}
+
+impl_lint_pass!(MacroUseImports => [MACRO_USE_IMPORTS]);
+
+impl<'l, 'txc> LateLintPass<'l, 'txc> for MacroUseImports {
+    fn check_item(&mut self, lcx: &LateContext<'_, '_>, item: &hir::Item<'_>) {
         if_chain! {
-            if ecx.sess.opts.edition == Edition::Edition2018;
-            if let ast::ItemKind::Use(use_tree) = &item.kind;
+            if lcx.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 import_path = snippet(ecx, use_tree.span, "_");
-                let mac_names = find_used_macros(ecx, &import_path);
-                let msg = "`macro_use` attributes are no longer needed in the Rust 2018 edition";
-                let help = format!("use {}::<macro name>", import_path);
-                span_lint_and_sugg(
-                    ecx,
-                    MACRO_USE_IMPORT,
-                    mac_attr.span,
-                    msg,
-                    // "remove the attribute and import the macro directly, try",
-                    "",
-                    help,
-                    Applicability::HasPlaceholders,
-                );
+                // println!("{:#?}", lcx.tcx.def_path_str(id));
+                for kid in lcx.tcx.item_children(id).iter() {
+                    // println!("{:#?}", kid);
+                    if let Res::Def(DefKind::Macro(_mac_type), mac_id) = kid.res {
+                        let span = mac_attr.span.clone();
+
+                        // println!("{:#?}", lcx.tcx.def_path_str(mac_id));
+
+                        self.imports.push((lcx.tcx.def_path_str(mac_id), span));
+                    }
+                }
+            } else {
+                if in_macro(item.span) {
+                    let call_site = item.span.source_callsite();
+                    let name = snippet(lcx, lcx.sess().source_map().span_until_char(call_site, '!'), "_");
+                    if let Some(callee) = item.span.source_callee() {
+                        if !self.collected.contains_key(&call_site) {
+                            let mac = MacroRefData::new(name.to_string(), callee.def_site, lcx);
+                            self.mac_refs.push((call_site, mac.clone()));
+                            self.collected.insert(call_site, mac);
+                        }
+                    }
+                }
             }
         }
     }
+    fn check_attribute(&mut self, lcx: &LateContext<'_, '_>, attr: &ast::Attribute) {
+        if in_macro(attr.span) {
+            let call_site = attr.span.source_callsite();
+            let name = snippet(lcx, lcx.sess().source_map().span_until_char(call_site, '!'), "_");
+            if let Some(callee) = attr.span.source_callee() {
+                if !self.collected.contains_key(&call_site) {
+                    println!("{:?}\n{:#?}", call_site, attr);
+
+                    let name = if name.contains("::") {
+                        name.split("::").last().unwrap().to_string()
+                    } else {
+                        name.to_string()
+                    };
 
-    fn check_expr(&mut self, ecx: &EarlyContext<'_>, expr: &ast::Expr) {
+                    let mac = MacroRefData::new(name, callee.def_site, lcx);
+                    self.mac_refs.push((call_site, mac.clone()));
+                    self.collected.insert(call_site, mac);
+                }
+            }
+        }
+    }
+    fn check_expr(&mut self, lcx: &LateContext<'_, '_>, expr: &hir::Expr<'_>) {
         if in_macro(expr.span) {
-            let name = snippet(ecx, ecx.sess.source_map().span_until_char(expr.span.source_callsite(), '!'), "_");
+            let call_site = expr.span.source_callsite();
+            let name = snippet(lcx, lcx.sess().source_map().span_until_char(call_site, '!'), "_");
             if let Some(callee) = expr.span.source_callee() {
-                if self.collected.insert(callee.def_site) {
-                    println!("EXPR {:#?}", name);
+                if !self.collected.contains_key(&call_site) {
+                    let name = if name.contains("::") {
+                        name.split("::").last().unwrap().to_string()
+                    } else {
+                        name.to_string()
+                    };
+
+                    let mac = MacroRefData::new(name, callee.def_site, lcx);
+                    self.mac_refs.push((call_site, mac.clone()));
+                    self.collected.insert(call_site, mac);
                 }
             }
         }
     }
-    fn check_stmt(&mut self, ecx: &EarlyContext<'_>, stmt: &ast::Stmt) {
+    fn check_stmt(&mut self, lcx: &LateContext<'_, '_>, stmt: &hir::Stmt<'_>) {
         if in_macro(stmt.span) {
-            let name = snippet(ecx, ecx.sess.source_map().span_until_char(stmt.span.source_callsite(), '!'), "_");
+            let call_site = stmt.span.source_callsite();
+            let name = snippet(lcx, lcx.sess().source_map().span_until_char(call_site, '!'), "_");
             if let Some(callee) = stmt.span.source_callee() {
-                println!("EXPR {:#?}", name);
+                if !self.collected.contains_key(&call_site) {
+                    let name = if name.contains("::") {
+                        name.split("::").last().unwrap().to_string()
+                    } else {
+                        name.to_string()
+                    };
+
+                    let mac = MacroRefData::new(name, callee.def_site, lcx);
+                    self.mac_refs.push((call_site, mac.clone()));
+                    self.collected.insert(call_site, mac);
+                }
             }
         }
     }
-    fn check_pat(&mut self, ecx: &EarlyContext<'_>, pat: &ast::Pat) {
+    fn check_pat(&mut self, lcx: &LateContext<'_, '_>, pat: &hir::Pat<'_>) {
         if in_macro(pat.span) {
-            let name = snippet(ecx, ecx.sess.source_map().span_until_char(pat.span.source_callsite(), '!'), "_");
+            let call_site = pat.span.source_callsite();
+            let name = snippet(lcx, lcx.sess().source_map().span_until_char(call_site, '!'), "_");
             if let Some(callee) = pat.span.source_callee() {
-                println!("EXPR {:#?}", name);
+                if !self.collected.contains_key(&call_site) {
+                    let mac = MacroRefData::new(name.to_string(), callee.def_site, lcx);
+                    self.mac_refs.push((call_site, mac.clone()));
+                    self.collected.insert(call_site, mac);
+                }
             }
         }
     }
-}
+    fn check_ty(&mut self, lcx: &LateContext<'_, '_>, ty: &hir::Ty<'_>) {
+        if in_macro(ty.span) {
+            let call_site = ty.span.source_callsite();
+            let name = snippet(lcx, lcx.sess().source_map().span_until_char(call_site, '!'), "_");
+            if let Some(callee) = ty.span.source_callee() {
+                if !self.collected.contains_key(&call_site) {
+                    let mac = MacroRefData::new(name.to_string(), callee.def_site, lcx);
+                    self.mac_refs.push((call_site, mac.clone()));
+                    self.collected.insert(call_site, mac);
+                }
+            }
+        }
+    }
+
+    fn check_crate_post(&mut self, lcx: &LateContext<'_, '_>, _krate: &hir::Crate<'_>) {
+        for (import, span) in self.imports.iter() {
+            let matched = self
+                .mac_refs
+                .iter()
+                .find(|(_span, mac)| import.ends_with(&mac.name))
+                .is_some();
 
-fn find_used_macros(ecx: &EarlyContext<'_>, path: &str) {
-    for it in ecx.krate.module.items.iter() {
-        if in_macro(it.span) {
-            // println!("{:#?}", it)
+            if matched {
+                self.mac_refs.retain(|(_span, mac)| !import.ends_with(&mac.name));
+                let msg = "`macro_use` attributes are no longer needed in the Rust 2018 edition";
+                let help = format!("use {}", import);
+                span_lint_and_sugg(
+                    lcx,
+                    MACRO_USE_IMPORTS,
+                    *span,
+                    msg,
+                    "remove the attribute and import the macro directly, try",
+                    help,
+                    Applicability::HasPlaceholders,
+                )
+            }
+        }
+        if !self.mac_refs.is_empty() {
+            // TODO if not empty we found one we could not make a suggestion for
+            // such as std::prelude::v1 or something else I haven't thought of.
+            // println!("{:#?}", self.mac_refs);
         }
     }
-    for x in ecx.sess.imported_macro_spans.borrow().iter() {
-        // println!("{:?}", x);
+}
+
+const PRELUDE: &[&str] = &[
+    "marker", "ops", "convert", "iter", "option", "result", "borrow", "boxed", "string", "vec", "macros",
+];
+
+/// This is somewhat of a fallback for imports from `std::prelude` because they
+/// are not recognized by `LateLintPass::check_item` `lcx.tcx.item_children(id)`
+fn make_path(mac: &MacroRefData, use_path: &str) -> String {
+    let segs = mac.path.split("::").filter(|s| *s != "").collect::<Vec<_>>();
+
+    if segs.starts_with(&["std"]) && PRELUDE.iter().any(|m| segs.contains(m)) {
+        return format!(
+            "std::prelude::{} is imported by default, remove `use` statement",
+            mac.name
+        );
+    }
+
+    if use_path.split("::").count() == 1 {
+        return format!("{}::{}", use_path, mac.name);
     }
+
+    mac.path.clone()
 }
diff --git a/macro_use_import b/macro_use_import
deleted file mode 100755
index 61d3a827f1f..00000000000
--- a/macro_use_import
+++ /dev/null
Binary files differdiff --git a/tests/ui/auxiliary/macro_use_helper.rs b/tests/ui/auxiliary/macro_use_helper.rs
new file mode 100644
index 00000000000..c63149a6819
--- /dev/null
+++ b/tests/ui/auxiliary/macro_use_helper.rs
@@ -0,0 +1,55 @@
+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::try_err;
+
+    // ITEM
+    #[macro_export]
+    macro_rules! inner_mod {
+        () => {
+            #[allow(dead_code)]
+            pub struct Tardis;
+        };
+    }
+}
+
+// EXPR
+#[macro_export]
+macro_rules! function {
+    () => {
+        if true {
+        } else {
+        }
+    };
+}
+
+// TYPE
+#[macro_export]
+macro_rules! ty_mac {
+    () => {
+        Vec<u8>
+    };
+}
+
+mod extern_exports {
+    pub(super) mod private_inner {
+        #[macro_export]
+        macro_rules! pub_in_private {
+            ($name:ident) => {
+                let $name = String::from("secrets and lies");
+            };
+        }
+    }
+}
diff --git a/tests/ui/macro_use_import.rs b/tests/ui/macro_use_import.rs
deleted file mode 100644
index 6490a2107d5..00000000000
--- a/tests/ui/macro_use_import.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-// compile-flags: --edition 2018
-#![warn(clippy::macro_use_import)]
-
-use std::collections::HashMap;
-#[macro_use]
-use std::prelude;
-
-fn main() {
-    let _ = HashMap::<u8, u8>::new();
-    serde_if_integer128!("");
-    println!();
-}
diff --git a/tests/ui/macro_use_import.stderr b/tests/ui/macro_use_import.stderr
deleted file mode 100644
index 1d86ba58441..00000000000
--- a/tests/ui/macro_use_import.stderr
+++ /dev/null
@@ -1,10 +0,0 @@
-error: `macro_use` attributes are no longer needed in the Rust 2018 edition
-  --> $DIR/macro_use_import.rs:5:1
-   |
-LL | #[macro_use]
-   | ^^^^^^^^^^^^ help: remove the attribute and import the macro directly, try: `use std::prelude::<macro name>`
-   |
-   = note: `-D clippy::macro-use-import` implied by `-D warnings`
-
-error: aborting due to previous error
-
diff --git a/tests/ui/macro_use_imports.rs b/tests/ui/macro_use_imports.rs
index 60c64ee8146..76911b0c565 100644
--- a/tests/ui/macro_use_imports.rs
+++ b/tests/ui/macro_use_imports.rs
@@ -1,11 +1,40 @@
-// edition:2018
+// compile-flags: --edition 2018
+// aux-build:macro_rules.rs
+// aux-build:macro_use_helper.rs
+
+#![allow(clippy::single_component_path_imports)]
 #![warn(clippy::macro_use_imports)]
 
-use std::collections::HashMap;
 #[macro_use]
-use std::prelude;
+extern crate macro_use_helper as mac;
+
+#[macro_use]
+extern crate clippy_mini_macro_test as mini_mac;
+
+mod a {
+    #[macro_use]
+    use std::prelude;
+    #[macro_use]
+    use mac;
+    #[macro_use]
+    use mini_mac;
+    #[macro_use]
+    use mac::inner;
+
+    #[derive(ClippyMiniMacroTest)]
+    struct Test;
+
+    fn main() {
+        pub_macro!();
+        inner_mod!();
+        pub_in_private!(_var);
+        function!();
+        let v: ty_mac!() = Vec::default();
+
+        inner::try_err!();
+    }
+}
 
 fn main() {
-    let _ = HashMap::<u8, u8>::new();
     println!();
 }