1 files changed, 30 insertions, 11 deletions

diff --git a/src/libexpr/eval-cache.cc b/src/libexpr/eval-cache.cc
index d7e21783d..188223957 100644
--- a/src/libexpr/eval-cache.cc
+++ b/src/libexpr/eval-cache.cc
@@ -336,7 +336,7 @@ Value & AttrCursor::getValue()
     if (!_value) {
         if (parent) {
             auto & vParent = parent->first->getValue();
-            root->state.forceAttrs(vParent);
+            root->state.forceAttrs(vParent, noPos);
             auto attr = vParent.attrs->get(parent->second);
             if (!attr)
                 throw Error("attribute '%s' is unexpectedly missing", getAttrPathStr());
@@ -381,7 +381,7 @@ Value & AttrCursor::forceValue()
     auto & v = getValue();
 
     try {
-        root->state.forceValue(v);
+        root->state.forceValue(v, noPos);
     } catch (EvalError &) {
         debug("setting '%s' to failed", getAttrPathStr());
         if (root->db)
@@ -406,6 +406,16 @@ Value & AttrCursor::forceValue()
     return v;
 }
 
+Suggestions AttrCursor::getSuggestionsForAttr(Symbol name)
+{
+    auto attrNames = getAttrs();
+    std::set<std::string> strAttrNames;
+    for (auto & name : attrNames)
+        strAttrNames.insert(std::string(name));
+
+    return Suggestions::bestMatches(strAttrNames, name);
+}
+
 std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErrors)
 {
     if (root->db) {
@@ -446,6 +456,11 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErro
         return nullptr;
         //throw TypeError("'%s' is not an attribute set", getAttrPathStr());
 
+    for (auto & attr : *v.attrs) {
+        if (root->db)
+            root->db->setPlaceholder({cachedValue->first, attr.name});
+    }
+
     auto attr = v.attrs->get(name);
 
     if (!attr) {
@@ -464,7 +479,7 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(Symbol name, bool forceErro
         cachedValue2 = {root->db->setPlaceholder({cachedValue->first, name}), placeholder_t()};
     }
 
-    return std::make_shared<AttrCursor>(
+    return make_ref<AttrCursor>(
         root, std::make_pair(shared_from_this(), name), attr->value, std::move(cachedValue2));
 }
 
@@ -473,27 +488,31 @@ std::shared_ptr<AttrCursor> AttrCursor::maybeGetAttr(std::string_view name)
     return maybeGetAttr(root->state.symbols.create(name));
 }
 
-std::shared_ptr<AttrCursor> AttrCursor::getAttr(Symbol name, bool forceErrors)
+ref<AttrCursor> AttrCursor::getAttr(Symbol name, bool forceErrors)
 {
     auto p = maybeGetAttr(name, forceErrors);
     if (!p)
         throw Error("attribute '%s' does not exist", getAttrPathStr(name));
-    return p;
+    return ref(p);
 }
 
-std::shared_ptr<AttrCursor> AttrCursor::getAttr(std::string_view name)
+ref<AttrCursor> AttrCursor::getAttr(std::string_view name)
 {
     return getAttr(root->state.symbols.create(name));
 }
 
-std::shared_ptr<AttrCursor> AttrCursor::findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force)
+OrSuggestions<ref<AttrCursor>> AttrCursor::findAlongAttrPath(const std::vector<Symbol> & attrPath, bool force)
 {
     auto res = shared_from_this();
     for (auto & attr : attrPath) {
-        res = res->maybeGetAttr(attr, force);
-        if (!res) return {};
+        auto child = res->maybeGetAttr(attr, force);
+        if (!child) {
+            auto suggestions = res->getSuggestionsForAttr(attr);
+            return OrSuggestions<ref<AttrCursor>>::failed(suggestions);
+        }
+        res = child;
     }
-    return res;
+    return ref(res);
 }
 
 std::string AttrCursor::getString()
@@ -596,7 +615,7 @@ std::vector<Symbol> AttrCursor::getAttrs()
     for (auto & attr : *getValue().attrs)
         attrs.push_back(attr.name);
     std::sort(attrs.begin(), attrs.end(), [](const Symbol & a, const Symbol & b) {
-        return (const string &) a < (const string &) b;
+        return (const std::string &) a < (const std::string &) b;
     });
 
     if (root->db)