Fixed two bugs that caused extra .value() emission, closes #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;
             }
         }