1 files changed, 179 insertions, 0 deletions

diff --git a/crates/ra_ide_api/src/references/classify.rs b/crates/ra_ide_api/src/references/classify.rs
new file mode 100644
index 000000000..c8daff9b1
--- /dev/null
+++ b/crates/ra_ide_api/src/references/classify.rs
@@ -0,0 +1,179 @@
+//! Functions that are used to classify an element from its definition or reference.
+
+use hir::{Either, FromSource, Module, ModuleSource, Path, PathResolution, Source, SourceAnalyzer};
+use ra_db::FileId;
+use ra_syntax::{ast, match_ast, AstNode, AstPtr};
+use test_utils::tested_by;
+
+use super::{
+    name_definition::{from_assoc_item, from_module_def, from_pat, from_struct_field},
+    NameDefinition, NameKind,
+};
+use crate::db::RootDatabase;
+
+pub(crate) fn classify_name(
+    db: &RootDatabase,
+    file_id: FileId,
+    name: &ast::Name,
+) -> Option<NameDefinition> {
+    let parent = name.syntax().parent()?;
+    let file_id = file_id.into();
+
+    // FIXME: add ast::MacroCall(it)
+    match_ast! {
+        match parent {
+            ast::BindPat(it) => {
+                from_pat(db, file_id, AstPtr::new(&it))
+            },
+            ast::RecordFieldDef(it) => {
+                let ast = hir::FieldSource::Named(it);
+                let src = hir::Source { file_id, ast };
+                let field = hir::StructField::from_source(db, src)?;
+                Some(from_struct_field(db, field))
+            },
+            ast::Module(it) => {
+                let def = {
+                    if !it.has_semi() {
+                        let ast = hir::ModuleSource::Module(it);
+                        let src = hir::Source { file_id, ast };
+                        hir::Module::from_definition(db, src)
+                    } else {
+                        let src = hir::Source { file_id, ast: it };
+                        hir::Module::from_declaration(db, src)
+                    }
+                }?;
+                Some(from_module_def(db, def.into(), None))
+            },
+            ast::StructDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::Struct::from_source(db, src)?;
+                Some(from_module_def(db, def.into(), None))
+            },
+            ast::EnumDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::Enum::from_source(db, src)?;
+                Some(from_module_def(db, def.into(), None))
+            },
+            ast::TraitDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::Trait::from_source(db, src)?;
+                Some(from_module_def(db, def.into(), None))
+            },
+            ast::StaticDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::Static::from_source(db, src)?;
+                Some(from_module_def(db, def.into(), None))
+            },
+            ast::EnumVariant(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::EnumVariant::from_source(db, src)?;
+                Some(from_module_def(db, def.into(), None))
+            },
+            ast::FnDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::Function::from_source(db, src)?;
+                if parent.parent().and_then(ast::ItemList::cast).is_some() {
+                    Some(from_assoc_item(db, def.into()))
+                } else {
+                    Some(from_module_def(db, def.into(), None))
+                }
+            },
+            ast::ConstDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::Const::from_source(db, src)?;
+                if parent.parent().and_then(ast::ItemList::cast).is_some() {
+                    Some(from_assoc_item(db, def.into()))
+                } else {
+                    Some(from_module_def(db, def.into(), None))
+                }
+            },
+            ast::TypeAliasDef(it) => {
+                let src = hir::Source { file_id, ast: it };
+                let def = hir::TypeAlias::from_source(db, src)?;
+                if parent.parent().and_then(ast::ItemList::cast).is_some() {
+                    Some(from_assoc_item(db, def.into()))
+                } else {
+                    Some(from_module_def(db, def.into(), None))
+                }
+            },
+            _ => None,
+        }
+    }
+}
+
+pub(crate) fn classify_name_ref(
+    db: &RootDatabase,
+    file_id: FileId,
+    name_ref: &ast::NameRef,
+) -> Option<NameDefinition> {
+    use PathResolution::*;
+
+    let parent = name_ref.syntax().parent()?;
+    let analyzer = SourceAnalyzer::new(db, file_id, name_ref.syntax(), None);
+
+    if let Some(method_call) = ast::MethodCallExpr::cast(parent.clone()) {
+        tested_by!(goto_definition_works_for_methods);
+        if let Some(func) = analyzer.resolve_method_call(&method_call) {
+            return Some(from_assoc_item(db, func.into()));
+        }
+    }
+
+    if let Some(field_expr) = ast::FieldExpr::cast(parent.clone()) {
+        tested_by!(goto_definition_works_for_fields);
+        if let Some(field) = analyzer.resolve_field(&field_expr) {
+            return Some(from_struct_field(db, field));
+        }
+    }
+
+    if let Some(record_field) = ast::RecordField::cast(parent.clone()) {
+        tested_by!(goto_definition_works_for_record_fields);
+        if let Some(record_lit) = record_field.syntax().ancestors().find_map(ast::RecordLit::cast) {
+            let variant_def = analyzer.resolve_record_literal(&record_lit)?;
+            let hir_path = Path::from_name_ref(name_ref);
+            let hir_name = hir_path.as_ident()?;
+            let field = variant_def.field(db, hir_name)?;
+            return Some(from_struct_field(db, field));
+        }
+    }
+
+    let ast = ModuleSource::from_child_node(db, file_id, &parent);
+    let file_id = file_id.into();
+    // FIXME: find correct container and visibility for each case
+    let container = Module::from_definition(db, Source { file_id, ast })?;
+    let visibility = None;
+
+    if let Some(macro_call) = parent.ancestors().find_map(ast::MacroCall::cast) {
+        tested_by!(goto_definition_works_for_macros);
+        if let Some(macro_def) = analyzer.resolve_macro_call(db, &macro_call) {
+            let kind = NameKind::Macro(macro_def);
+            return Some(NameDefinition { kind, container, visibility });
+        }
+    }
+
+    let path = name_ref.syntax().ancestors().find_map(ast::Path::cast)?;
+    let resolved = analyzer.resolve_path(db, &path)?;
+    match resolved {
+        Def(def) => Some(from_module_def(db, def, Some(container))),
+        AssocItem(item) => Some(from_assoc_item(db, item)),
+        LocalBinding(Either::A(pat)) => from_pat(db, file_id, pat),
+        LocalBinding(Either::B(par)) => {
+            let kind = NameKind::SelfParam(par);
+            Some(NameDefinition { kind, container, visibility })
+        }
+        GenericParam(par) => {
+            // FIXME: get generic param def
+            let kind = NameKind::GenericParam(par);
+            Some(NameDefinition { kind, container, visibility })
+        }
+        Macro(def) => {
+            let kind = NameKind::Macro(def);
+            Some(NameDefinition { kind, container, visibility })
+        }
+        SelfType(impl_block) => {
+            let ty = impl_block.target_ty(db);
+            let kind = NameKind::SelfType(ty);
+            let container = impl_block.module();
+            Some(NameDefinition { kind, container, visibility })
+        }
+    }
+}