Fixed two bugs that caused extra .value() emission, closes hsutter#29

First, local variable name lookup should stay within the current function and not find any locals not in a directly nested scope Second, we shouldn't be adding `.value()` to names of non-locals (such as the names of members being accessed) Added regression test

Author: hsutter

regression-tests/pure2-bugfix-for-name-lookup-and-value-decoration.cpp2

@@ -0,0 +1,9 @@
+vals: () -> (i : int) = {
+ i = 42;
+ return;
+}
+
+main: () -> int = {
+ v := vals();
+ v.i;
+}

regression-tests/test-results/pure2-bugfix-for-name-lookup-and-value-decoration.cpp

@@ -0,0 +1,28 @@
+// ----- Cpp2 support -----
+#define CPP2_USE_MODULES Yes
+#include "cpp2util.h"
+
+
+#line 1 "pure2-bugfix-for-name-lookup-and-value-decoration.cpp2"
+struct vals__ret {
+ int i;
+ };
+#line 2 "pure2-bugfix-for-name-lookup-and-value-decoration.cpp2"
+[[nodiscard]] auto vals() -> vals__ret;
+#line 6 "pure2-bugfix-for-name-lookup-and-value-decoration.cpp2"
+[[nodiscard]] auto main() -> int;
+
+//=== Cpp2 definitions ==========================================================
+
+#line 1 "pure2-bugfix-for-name-lookup-and-value-decoration.cpp2"
+[[nodiscard]] auto vals() -> vals__ret{
+ cpp2::deferred_init<int> i;
+#line 2 "pure2-bugfix-for-name-lookup-and-value-decoration.cpp2"
+ i.construct(42);
+ return { std::move(i.value()) }; 
+}
+
+[[nodiscard]] auto main() -> int{
+ auto v { vals() }; 
+ v.i;
+}

regression-tests/test-results/pure2-bugfix-for-name-lookup-and-value-decoration.cpp2.output

@@ -0,0 +1,2 @@
+pure2-bugfix-for-name-lookup-and-value-decoration.cpp2... ok (all Cpp2, passes safety checks)
+

source/cppfront.cpp

@@ -1007,7 +1007,12 @@ class cppfront
 
  //-----------------------------------------------------------------------
  //
- auto emit(unqualified_id_node const& n, bool in_synthesized_multi_return = false ) -> void
+ auto emit(
+ unqualified_id_node const& n,
+ bool in_synthesized_multi_return = false,
+ bool is_local_name = true
+ )
+ -> void
  {
  auto last_use = is_definite_last_use(n.identifier);
 
@@ -1053,6 +1058,7 @@ class cppfront
  }
  else if (!in_definite_init && !in_parameter_list) {
  if (auto decl = sema.get_declaration_of(*n.identifier);
+ is_local_name &&
  decl &&
  // note pointer equality: if we're not in the actual declaration of n.identifier
  decl->identifier != n.identifier &&
@@ -1104,10 +1110,10 @@ class cppfront
 
  //-----------------------------------------------------------------------
  //
- auto emit(id_expression_node const& n) -> void
+ auto emit(id_expression_node const& n, bool is_local_name = true) -> void
  {
  try_emit<id_expression_node::qualified >(n.id);
- try_emit<id_expression_node::unqualified>(n.id);
+ try_emit<id_expression_node::unqualified>(n.id, false, is_local_name);
  }
 
 
@@ -1730,7 +1736,7 @@ class cppfront
  if (i->id_expr) {
  auto print = std::string{};
  printer.emit_to_string(&print);
- emit(*i->id_expr);
+ emit(*i->id_expr, false /*not a local name*/);
  printer.emit_to_string();
  suffix.emplace_back( print, i->id_expr->position() );
  }

source/sema.h

@@ -244,12 +244,23 @@ class sema
 
  // Then look backward to find the first declaration of
  // this name that is not deeper (in a nested scope)
- for ( ; i != symbols.cbegin(); --i ) {
- if (i->sym.index() == symbol::active::declaration && i->depth <= depth) {
+ for ( ; i != symbols.cbegin(); --i )
+ {
+ if (i->sym.index() == symbol::active::declaration && i->depth <= depth)
+ {
  auto const& decl = std::get<symbol::active::declaration>(i->sym);
+
+ // Don't look beyond the current function
+ assert(decl.declaration);
+ if (decl.declaration->type.index() == declaration_node::function) {
+ return nullptr;
+ }
+
+ // If the name matches, this is it
  if (decl.identifier && *decl.identifier == t) {
  return &decl;
  }
+ depth = i->depth;
  }
  }