1 files changed, 95 insertions, 0 deletions

diff --git a/crates/ra_ide_api/src/name_ref_kind.rs b/crates/ra_ide_api/src/name_ref_kind.rs
new file mode 100644
index 000000000..b498fe495
--- /dev/null
+++ b/crates/ra_ide_api/src/name_ref_kind.rs
@@ -0,0 +1,95 @@
+use ra_syntax::{AstNode, AstPtr, ast};
+use hir::Either;
+use crate::db::RootDatabase;
+use test_utils::tested_by;
+
+pub enum NameRefKind {
+    Method(hir::Function),
+    Macro(hir::MacroByExampleDef),
+    FieldAccess(hir::StructField),
+    AssocItem(hir::ImplItem),
+    Def(hir::ModuleDef),
+    SelfType(hir::Ty),
+    Pat(AstPtr<ast::Pat>),
+    SelfParam(AstPtr<ast::SelfParam>),
+    GenericParam(u32),
+}
+
+pub(crate) fn classify_name_ref(
+    db: &RootDatabase,
+    analyzer: &hir::SourceAnalyzer,
+    name_ref: &ast::NameRef,
+) -> Option<NameRefKind> {
+    use NameRefKind::*;
+
+    // Check if it is a method
+    if let Some(method_call) = name_ref.syntax().parent().and_then(ast::MethodCallExpr::cast) {
+        tested_by!(goto_definition_works_for_methods);
+        if let Some(func) = analyzer.resolve_method_call(method_call) {
+            return Some(Method(func));
+        }
+    }
+
+    // It could be a macro call
+    if let Some(macro_call) = name_ref
+        .syntax()
+        .parent()
+        .and_then(|node| node.parent())
+        .and_then(|node| node.parent())
+        .and_then(ast::MacroCall::cast)
+    {
+        tested_by!(goto_definition_works_for_macros);
+        if let Some(mac) = analyzer.resolve_macro_call(macro_call) {
+            return Some(Macro(mac));
+        }
+    }
+
+    // It could also be a field access
+    if let Some(field_expr) = name_ref.syntax().parent().and_then(ast::FieldExpr::cast) {
+        tested_by!(goto_definition_works_for_fields);
+        if let Some(field) = analyzer.resolve_field(field_expr) {
+            return Some(FieldAccess(field));
+        };
+    }
+
+    // It could also be a named field
+    if let Some(field_expr) = name_ref.syntax().parent().and_then(ast::NamedField::cast) {
+        tested_by!(goto_definition_works_for_named_fields);
+
+        let struct_lit = field_expr.syntax().ancestors().find_map(ast::StructLit::cast);
+
+        if let Some(ty) = struct_lit.and_then(|lit| analyzer.type_of(db, lit.into())) {
+            if let Some((hir::AdtDef::Struct(s), _)) = ty.as_adt() {
+                let hir_path = hir::Path::from_name_ref(name_ref);
+                let hir_name = hir_path.as_ident().unwrap();
+
+                if let Some(field) = s.field(db, hir_name) {
+                    return Some(FieldAccess(field));
+                }
+            }
+        }
+    }
+
+    // General case, a path or a local:
+    if let Some(path) = name_ref.syntax().ancestors().find_map(ast::Path::cast) {
+        if let Some(resolved) = analyzer.resolve_path(db, path) {
+            return match resolved {
+                hir::PathResolution::Def(def) => Some(Def(def)),
+                hir::PathResolution::LocalBinding(Either::A(pat)) => Some(Pat(pat)),
+                hir::PathResolution::LocalBinding(Either::B(par)) => Some(SelfParam(par)),
+                hir::PathResolution::GenericParam(par) => {
+                    // FIXME: get generic param def
+                    Some(GenericParam(par))
+                }
+                hir::PathResolution::Macro(def) => Some(Macro(def)),
+                hir::PathResolution::SelfType(impl_block) => {
+                    let ty = impl_block.target_ty(db);
+                    Some(SelfType(ty))
+                }
+                hir::PathResolution::AssocItem(assoc) => Some(AssocItem(assoc)),
+            };
+        }
+    }
+
+    None
+}