From 30e7a1b2b34d14d533630a35abc0cd64b397fbba Mon Sep 17 00:00:00 2001
From: Yingchi Long <i@lyc.dev>
Date: Thu, 18 Apr 2024 11:01:51 +0800
Subject: [PATCH] libnixf: support parsing extra dot after attrpath (#428)

---
 libnixf/include/nixf/Basic/Nodes/Attrs.h | 11 ++++++++---
 libnixf/src/Parse/ParseAttrs.cpp         |  5 ++++-
 libnixf/src/Sema/SemaActions.cpp         |  3 ++-
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/libnixf/include/nixf/Basic/Nodes/Attrs.h b/libnixf/include/nixf/Basic/Nodes/Attrs.h
index cb9b398c2..ec0d9f4ae 100644
--- a/libnixf/include/nixf/Basic/Nodes/Attrs.h
+++ b/libnixf/include/nixf/Basic/Nodes/Attrs.h
@@ -89,10 +89,14 @@ class AttrName : public Node {
 
 class AttrPath : public Node {
   const std::vector<std::shared_ptr<AttrName>> Names;
+  // FIXME: workaround for just recording the trailing dot.
+  const std::shared_ptr<Misc> TrailingDot;
 
 public:
-  AttrPath(LexerCursorRange Range, std::vector<std::shared_ptr<AttrName>> Names)
-      : Node(NK_AttrPath, Range), Names(std::move(Names)) {}
+  AttrPath(LexerCursorRange Range, std::vector<std::shared_ptr<AttrName>> Names,
+           std::shared_ptr<Misc> TrailingDot)
+      : Node(NK_AttrPath, Range), Names(std::move(Names)),
+        TrailingDot(std::move(TrailingDot)) {}
 
   [[nodiscard]] const std::vector<std::shared_ptr<AttrName>> &names() const {
     return Names;
@@ -100,10 +104,11 @@ class AttrPath : public Node {
 
   [[nodiscard]] ChildVector children() const override {
     ChildVector Children;
-    Children.reserve(Names.size());
+    Children.reserve(Names.size() + 1);
     for (const auto &Name : Names) {
       Children.push_back(Name.get());
     }
+    Children.emplace_back(TrailingDot.get());
     return Children;
   }
 };
diff --git a/libnixf/src/Parse/ParseAttrs.cpp b/libnixf/src/Parse/ParseAttrs.cpp
index 01a6a9b48..bd025756b 100644
--- a/libnixf/src/Parse/ParseAttrs.cpp
+++ b/libnixf/src/Parse/ParseAttrs.cpp
@@ -36,6 +36,7 @@ std::shared_ptr<AttrPath> Parser::parseAttrPath() {
   assert(LastToken && "LastToken should be set after valid attrname");
   std::vector<std::shared_ptr<AttrName>> AttrNames;
   AttrNames.emplace_back(std::move(First));
+  std::shared_ptr<Misc> TrailingDot;
   while (true) {
     if (Token Tok = peek(); Tok.kind() == tok_dot) {
       consume();
@@ -47,6 +48,7 @@ std::shared_ptr<AttrPath> Parser::parseAttrPath() {
         D.fix("remove extra .").edit(TextEdit::mkRemoval(Tok.range()));
         D.fix("insert dummy attrname")
             .edit(TextEdit::mkInsertion(Tok.rCur(), R"("dummy")"));
+        TrailingDot = std::make_shared<Misc>(Tok.range());
         continue;
       }
       AttrNames.emplace_back(std::move(Next));
@@ -55,7 +57,8 @@ std::shared_ptr<AttrPath> Parser::parseAttrPath() {
     break;
   }
   return std::make_shared<AttrPath>(LexerCursorRange{Begin, LastToken->rCur()},
-                                    std::move(AttrNames));
+                                    std::move(AttrNames),
+                                    std::move(TrailingDot));
 }
 
 std::shared_ptr<Binding> Parser::parseBinding() {
diff --git a/libnixf/src/Sema/SemaActions.cpp b/libnixf/src/Sema/SemaActions.cpp
index 206a6915c..22546b7d2 100644
--- a/libnixf/src/Sema/SemaActions.cpp
+++ b/libnixf/src/Sema/SemaActions.cpp
@@ -330,7 +330,8 @@ std::shared_ptr<Expr> Sema::desugarInheritExpr(std::shared_ptr<AttrName> Name,
     return std::make_shared<ExprVar>(Range, Name->id());
 
   auto Path = std::make_shared<AttrPath>(
-      Range, std::vector<std::shared_ptr<AttrName>>{std::move(Name)});
+      Range, std::vector<std::shared_ptr<AttrName>>{std::move(Name)},
+      /*TrailingDot=*/nullptr);
   return std::make_shared<ExprSelect>(Range, std::move(E), std::move(Path),
                                       nullptr);
 }