fix(sema): pop consecutive implicit else branches

Author: JohelEGP

regression-tests/pure2-last-use.cpp2

@@ -79,6 +79,17 @@ issue_857_3: @struct type = {
   f: (move this) = _ = f_inout(i);
 }
 
+
+issue_884_3: () = {
+  x := new<int>(0);
+  if true { }
+  if true { }
+  {
+    { f_inout(x); }
+    f_copy(x);
+  }
+}
+
 issue_884: () = {
   x := new<int>(0);
   if true { }

regression-tests/test-results/pure2-last-use.cpp

@@ -20,7 +20,7 @@ class issue_857_2;
 class issue_857_3;
 
 
-#line 112 "pure2-last-use.cpp2"
+#line 123 "pure2-last-use.cpp2"
 class my_string;
 
 
@@ -88,18 +88,22 @@ class issue_857_3 {
   public: auto f() && -> void;
 };
 
+#line 83 "pure2-last-use.cpp2"
+auto issue_884_3() -> void;
+
+#line 93 "pure2-last-use.cpp2"
 auto issue_884() -> void;
 
-#line 91 "pure2-last-use.cpp2"
+#line 102 "pure2-last-use.cpp2"
 auto issue_884_2() -> void;
 
-#line 100 "pure2-last-use.cpp2"
+#line 111 "pure2-last-use.cpp2"
 auto issue_888(std::string r, int size) -> void;
 
-#line 106 "pure2-last-use.cpp2"
+#line 117 "pure2-last-use.cpp2"
 auto draw() -> void;
 
-#line 112 "pure2-last-use.cpp2"
+#line 123 "pure2-last-use.cpp2"
 class my_string {
   public: std::string string; 
   public: std::size_t size {CPP2_UFCS(size)(string)}; 
@@ -193,7 +197,17 @@ int gi {0};
 #line 79 "pure2-last-use.cpp2"
   auto issue_857_3::f() && -> void { static_cast<void>(f_inout(std::move(*this).i));  }
 
-#line 82 "pure2-last-use.cpp2"
+#line 83 "pure2-last-use.cpp2"
+auto issue_884_3() -> void{
+  auto x {cpp2_new<int>(0)}; 
+  if (true) {}
+  if (true) {}
+  {
+    {f_inout(x); }
+    f_copy(std::move(x));
+  }
+}
+
 auto issue_884() -> void{
   auto x {cpp2_new<int>(0)}; 
   if (true) {}
@@ -224,10 +238,10 @@ auto draw() -> void{
   static_cast<void>(CPP2_UFCS_MOVE(vertex)((std::move(pos))));
 }
 
-#line 117 "pure2-last-use.cpp2"
+#line 128 "pure2-last-use.cpp2"
 auto main(int const argc_, char** argv_) -> int{
   auto const args = cpp2::make_args(argc_, argv_); 
-#line 118 "pure2-last-use.cpp2"
+#line 129 "pure2-last-use.cpp2"
   issue_683(args);
   issue_847_2(std::vector<std::unique_ptr<int>>());
 }

source/sema.h

@@ -1935,19 +1935,24 @@ class sema
         );
         --scope_depth;
 
-        //  Pop an implicit 'else' branch.
-        if (auto s = std::find_if(
-                         symbols.rbegin(),
-                         symbols.rend(),
-                         [=](symbol s) {
-                             return s.depth == scope_depth;
-                         });
-            s != symbols.rend()
-            && std::get_if<symbol::selection>(&s->sym)
-            )
-        {
-            --scope_depth;
-        }
+        auto pop_implicit_else_branch = [&]() -> bool {
+            if (auto s = std::find_if(
+                             symbols.rbegin(),
+                             symbols.rend(),
+                             [=](symbol s) {
+                                 return s.depth <= scope_depth;
+                             });
+                s != symbols.rend()
+                && std::get_if<symbol::selection>(&s->sym)
+                && s->depth == scope_depth
+                )
+            {
+                --scope_depth;
+                return true;
+            }
+            return false;
+        };
+        while (pop_implicit_else_branch()) { }
     }
 
     auto start(assignment_expression_node const& n, int)