Auto merge of #14445 - Veykril:adt-flags, r=Veykril

internal: Introduce StructFlags

crates/hir-def/src/adt.rs

@@ -3,6 +3,7 @@
 use std::sync::Arc;
 
 use base_db::CrateId;
+use bitflags::bitflags;
 use cfg::CfgOptions;
 use either::Either;
 
@@ -20,6 +21,7 @@ use crate::{
     builtin_type::{BuiltinInt, BuiltinUint},
     db::DefDatabase,
     item_tree::{AttrOwner, Field, FieldAstId, Fields, ItemTree, ModItem, RawVisibilityId},
+    lang_item::LangItem,
     layout::{Align, ReprFlags, ReprOptions},
     nameres::diagnostics::DefDiagnostic,
     src::HasChildSource,
@@ -39,8 +41,26 @@ pub struct StructData {
     pub variant_data: Arc<VariantData>,
     pub repr: Option<ReprOptions>,
     pub visibility: RawVisibility,
-    pub rustc_has_incoherent_inherent_impls: bool,
-    pub fundamental: bool,
+    pub flags: StructFlags,
+}
+
+bitflags! {
+    pub struct StructFlags: u8 {
+        const NO_FLAGS         = 0;
+        /// Indicates whether the struct is `PhantomData`.
+        const IS_PHANTOM_DATA  = 1 << 2;
+        /// Indicates whether the struct has a `#[fundamental]` attribute.
+        const IS_FUNDAMENTAL   = 1 << 3;
+        // FIXME: should this be a flag?
+        /// Indicates whether the struct has a `#[rustc_has_incoherent_inherent_impls]` attribute.
+        const IS_RUSTC_HAS_INCOHERENT_INHERENT_IMPL      = 1 << 4;
+        /// Indicates whether this struct is `Box`.
+        const IS_BOX           = 1 << 5;
+        /// Indicates whether this struct is `ManuallyDrop`.
+        const IS_MANUALLY_DROP = 1 << 6;
+        /// Indicates whether this struct is `UnsafeCell`.
+        const IS_UNSAFE_CELL   = 1 << 6;
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -174,10 +194,25 @@ impl StructData {
         let item_tree = loc.id.item_tree(db);
         let repr = repr_from_value(db, krate, &item_tree, ModItem::from(loc.id.value).into());
         let cfg_options = db.crate_graph()[loc.container.krate].cfg_options.clone();
+
         let attrs = item_tree.attrs(db, loc.container.krate, ModItem::from(loc.id.value).into());
-        let rustc_has_incoherent_inherent_impls =
-            attrs.by_key("rustc_has_incoherent_inherent_impls").exists();
-        let fundamental = attrs.by_key("fundamental").exists();
+
+        let mut flags = StructFlags::NO_FLAGS;
+        if attrs.by_key("rustc_has_incoherent_inherent_impls").exists() {
+            flags |= StructFlags::IS_RUSTC_HAS_INCOHERENT_INHERENT_IMPL;
+        }
+        if attrs.by_key("fundamental").exists() {
+            flags |= StructFlags::IS_FUNDAMENTAL;
+        }
+        if let Some(lang) = attrs.lang_item() {
+            match lang {
+                LangItem::PhantomData => flags |= StructFlags::IS_PHANTOM_DATA,
+                LangItem::OwnedBox => flags |= StructFlags::IS_BOX,
+                LangItem::ManuallyDrop => flags |= StructFlags::IS_MANUALLY_DROP,
+                LangItem::UnsafeCell => flags |= StructFlags::IS_UNSAFE_CELL,
+                _ => (),
+            }
+        }
 
         let strukt = &item_tree[loc.id.value];
         let (variant_data, diagnostics) = lower_fields(
@@ -196,8 +231,7 @@ impl StructData {
                 variant_data: Arc::new(variant_data),
                 repr,
                 visibility: item_tree[strukt.visibility].clone(),
-                rustc_has_incoherent_inherent_impls,
-                fundamental,
+                flags,
             }),
             diagnostics.into(),
         )
@@ -218,9 +252,13 @@ impl StructData {
         let cfg_options = db.crate_graph()[loc.container.krate].cfg_options.clone();
 
         let attrs = item_tree.attrs(db, loc.container.krate, ModItem::from(loc.id.value).into());
-        let rustc_has_incoherent_inherent_impls =
-            attrs.by_key("rustc_has_incoherent_inherent_impls").exists();
-        let fundamental = attrs.by_key("fundamental").exists();
+        let mut flags = StructFlags::NO_FLAGS;
+        if attrs.by_key("rustc_has_incoherent_inherent_impls").exists() {
+            flags |= StructFlags::IS_RUSTC_HAS_INCOHERENT_INHERENT_IMPL;
+        }
+        if attrs.by_key("fundamental").exists() {
+            flags |= StructFlags::IS_FUNDAMENTAL;
+        }
 
         let union = &item_tree[loc.id.value];
         let (variant_data, diagnostics) = lower_fields(
@@ -239,8 +277,7 @@ impl StructData {
                 variant_data: Arc::new(variant_data),
                 repr,
                 visibility: item_tree[union.visibility].clone(),
-                rustc_has_incoherent_inherent_impls,
-                fundamental,
+                flags,
             }),
             diagnostics.into(),
         )

crates/hir-def/src/attr.rs

@@ -20,6 +20,7 @@ use syntax::{
 use crate::{
     db::DefDatabase,
     item_tree::{AttrOwner, Fields, ItemTreeId, ItemTreeNode},
+    lang_item::LangItem,
     nameres::{ModuleOrigin, ModuleSource},
     src::{HasChildSource, HasSource},
     AdtId, AttrDefId, EnumId, GenericParamId, LocalEnumVariantId, LocalFieldId, Lookup, MacroId,
@@ -177,13 +178,13 @@ impl Attrs {
 
         Arc::new(res)
     }
-
-    pub fn by_key(&self, key: &'static str) -> AttrQuery<'_> {
-        AttrQuery { attrs: self, key }
-    }
 }
 
 impl Attrs {
+    pub fn by_key(&self, key: &'static str) -> AttrQuery<'_> {
+        AttrQuery { attrs: self, key }
+    }
+
     pub fn cfg(&self) -> Option<CfgExpr> {
         let mut cfgs = self.by_key("cfg").tt_values().map(CfgExpr::parse);
         let first = cfgs.next()?;
@@ -206,6 +207,10 @@ impl Attrs {
         self.by_key("lang").string_value()
     }
 
+    pub fn lang_item(&self) -> Option<LangItem> {
+        self.by_key("lang").string_value().and_then(|it| LangItem::from_str(it))
+    }
+
     pub fn docs(&self) -> Option<Documentation> {
         let docs = self.by_key("doc").attrs().filter_map(|attr| attr.string_value());
         let indent = doc_indent(self);