Merge #4234

4234: Support local_inner_macros r=jonas-schievink a=edwin0cheng

This PR implements `#[macro_export(local_inner_macros)]` support. 

Note that the rustc implementation is quite [hacky][1] too. :)

[1]: https://github.com/rust-lang/rust/blob/614f273e9388ddd7804d5cbc80b8865068a3744e/src/librustc_resolve/macros.rs#L456

Co-authored-by: Edwin Cheng <[email protected]>

6 files changed, 80 insertions, 5 deletions

diff --git a/crates/ra_hir_def/src/attr.rs b/crates/ra_hir_def/src/attr.rs
index 5a86af8ba..576cd0c65 100644
--- a/crates/ra_hir_def/src/attr.rs
+++ b/crates/ra_hir_def/src/attr.rs
@@ -140,6 +140,7 @@ impl Attr {
     }
 }
 
+#[derive(Debug, Clone, Copy)]
 pub struct AttrQuery<'a> {
     attrs: &'a Attrs,
     key: &'static str,
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index 58b3d10d8..687216dc3 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -466,6 +466,7 @@ impl ExprCollector<'_> {
                         krate: Some(self.expander.module.krate),
                         ast_id: Some(self.expander.ast_id(&e)),
                         kind: MacroDefKind::Declarative,
+                        local_inner: false,
                     };
                     self.body.item_scope.define_legacy_macro(name, mac);
 
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 98c74fe25..bf3968bd6 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -204,6 +204,7 @@ impl DefCollector<'_> {
                 ast_id: None,
                 krate: Some(krate),
                 kind: MacroDefKind::CustomDerive(expander),
+                local_inner: false,
             };
 
             self.define_proc_macro(name.clone(), macro_id);
@@ -941,6 +942,7 @@ impl ModCollector<'_, '_> {
                     ast_id: Some(ast_id.ast_id),
                     krate: Some(self.def_collector.def_map.krate),
                     kind: MacroDefKind::Declarative,
+                    local_inner: mac.local_inner,
                 };
                 self.def_collector.define_macro(self.module_id, name.clone(), macro_id, mac.export);
             }
diff --git a/crates/ra_hir_def/src/nameres/raw.rs b/crates/ra_hir_def/src/nameres/raw.rs
index 39b011ad7..a71503c76 100644
--- a/crates/ra_hir_def/src/nameres/raw.rs
+++ b/crates/ra_hir_def/src/nameres/raw.rs
@@ -188,6 +188,7 @@ pub(super) struct MacroData {
     pub(super) path: ModPath,
     pub(super) name: Option<Name>,
     pub(super) export: bool,
+    pub(super) local_inner: bool,
     pub(super) builtin: bool,
 }
 
@@ -401,14 +402,32 @@ impl RawItemsCollector {
 
         let name = m.name().map(|it| it.as_name());
         let ast_id = self.source_ast_id_map.ast_id(&m);
-        // FIXME: cfg_attr
-        let export = m.attrs().filter_map(|x| x.simple_name()).any(|name| name == "macro_export");
 
         // FIXME: cfg_attr
-        let builtin =
-            m.attrs().filter_map(|x| x.simple_name()).any(|name| name == "rustc_builtin_macro");
+        let export_attr = attrs.by_key("macro_export");
+
+        let export = export_attr.exists();
+        let local_inner = if export {
+            export_attr.tt_values().map(|it| &it.token_trees).flatten().any(|it| match it {
+                tt::TokenTree::Leaf(tt::Leaf::Ident(ident)) => {
+                    ident.text.contains("local_inner_macros")
+                }
+                _ => false,
+            })
+        } else {
+            false
+        };
+
+        let builtin = attrs.by_key("rustc_builtin_macro").exists();
 
-        let m = self.raw_items.macros.alloc(MacroData { ast_id, path, name, export, builtin });
+        let m = self.raw_items.macros.alloc(MacroData {
+            ast_id,
+            path,
+            name,
+            export,
+            local_inner,
+            builtin,
+        });
         self.push_item(current_module, attrs, RawItemKind::Macro(m));
     }
 
diff --git a/crates/ra_hir_def/src/nameres/tests/macros.rs b/crates/ra_hir_def/src/nameres/tests/macros.rs
index b0befdfbd..9bc0e6287 100644
--- a/crates/ra_hir_def/src/nameres/tests/macros.rs
+++ b/crates/ra_hir_def/src/nameres/tests/macros.rs
@@ -136,6 +136,43 @@ fn macro_rules_export_with_local_inner_macros_are_visible() {
 }
 
 #[test]
+fn local_inner_macros_makes_local_macros_usable() {
+    let map = def_map(
+        "
+        //- /main.rs crate:main deps:foo
+        foo::structs!(Foo, Bar);
+        mod bar;
+        //- /bar.rs
+        use crate::*;
+        //- /lib.rs crate:foo
+        #[macro_export(local_inner_macros)]
+        macro_rules! structs {
+            ($($i:ident),*) => {
+                inner!($($i),*);
+            }
+        }
+        #[macro_export]
+        macro_rules! inner {
+            ($($i:ident),*) => {
+                $(struct $i { field: u32 } )*
+            }
+        }
+        ",
+    );
+    assert_snapshot!(map, @r###"
+   ⋮crate
+   ⋮Bar: t v
+   ⋮Foo: t v
+   ⋮bar: t
+   ⋮
+   ⋮crate::bar
+   ⋮Bar: t v
+   ⋮Foo: t v
+   ⋮bar: t
+    "###);
+}
+
+#[test]
 fn unexpanded_macro_should_expand_by_fixedpoint_loop() {
     let map = def_map(
         "
diff --git a/crates/ra_hir_def/src/path/lower.rs b/crates/ra_hir_def/src/path/lower.rs
index e3d237a0a..6a0c019fd 100644
--- a/crates/ra_hir_def/src/path/lower.rs
+++ b/crates/ra_hir_def/src/path/lower.rs
@@ -116,6 +116,21 @@ pub(super) fn lower_path(mut path: ast::Path, hygiene: &Hygiene) -> Option<Path>
     }
     segments.reverse();
     generic_args.reverse();
+
+    // handle local_inner_macros :
+    // Basically, even in rustc it is quite hacky:
+    // https://github.com/rust-lang/rust/blob/614f273e9388ddd7804d5cbc80b8865068a3744e/src/librustc_resolve/macros.rs#L456
+    // We follow what it did anyway :)
+    if segments.len() == 1 && kind == PathKind::Plain {
+        if let Some(macro_call) = path.syntax().parent().and_then(ast::MacroCall::cast) {
+            if macro_call.is_bang() {
+                if let Some(crate_id) = hygiene.local_inner_macros() {
+                    kind = PathKind::DollarCrate(crate_id);
+                }
+            }
+        }
+    }
+
     let mod_path = ModPath { kind, segments };
     return Some(Path { type_anchor, mod_path, generic_args });