libstdc++: Fix return value of vector::insert_range

In some cases we're wrongly returning an iterator to (one past) the last
element inserted instead of to the first element inserted.

libstdc++-v3/ChangeLog:

	* include/bits/stl_bvector.h (vector<bool>::insert_range):
	Consistently return an iterator pointing to the first element
	inserted.
	* include/bits/vector.tcc (vector::insert_range): Likewise.
	* testsuite/23_containers/vector/bool/modifiers/insert/insert_range.cc:
	Verify insert_range return values.
	* testsuite/23_containers/vector/modifiers/insert/insert_range.cc:
	Likewise.

Reviewed-by: Jonathan Wakely <jwakely@redhat.com>

4 files changed, 30 insertions, 17 deletions

diff --git a/libstdc++-v3/include/bits/stl_bvector.h b/libstdc++-v3/include/bits/stl_bvector.h
index 961e4a2..2292eec 100644
--- a/libstdc++-v3/include/bits/stl_bvector.h
+++ b/libstdc++-v3/include/bits/stl_bvector.h
@@ -1341,9 +1341,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 		      std::copy_backward(__pos._M_const_cast(), end(),
 					 this->_M_impl._M_finish
 					   + difference_type(__n));
-		      auto __i = ranges::copy(__rg, __pos._M_const_cast()).out;
+		      ranges::copy(__rg, __pos._M_const_cast());
 		      this->_M_impl._M_finish += difference_type(__n);
-		      return __i;
+		      return __pos._M_const_cast();
 		    }
 		  else
 		    {
@@ -1355,9 +1355,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 		      iterator __i = _M_copy_aligned(__begin,
 						     __pos._M_const_cast(),
 						     __start);
-		      __i = ranges::copy(__rg, __i).out;
+		      iterator __j = ranges::copy(__rg, __i).out;
 		      iterator __finish = std::copy(__pos._M_const_cast(),
-						    __end, __i);
+						    __end, __j);
 		      this->_M_deallocate();
 		      this->_M_impl._M_end_of_storage = __q + _S_nword(__len);
 		      this->_M_impl._M_start = __start;
diff --git a/libstdc++-v3/include/bits/vector.tcc b/libstdc++-v3/include/bits/vector.tcc
index 4f4c366..acb2f5f 100644
--- a/libstdc++-v3/include/bits/vector.tcc
+++ b/libstdc++-v3/include/bits/vector.tcc
@@ -984,8 +984,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       {
 	if (__pos == cend())
 	  {
+	    const auto __ins_idx = size();
 	    append_range(std::forward<_Rg>(__rg));
-	    return end();
+	    return begin() + __ins_idx;
 	  }
 
 	if constexpr (ranges::forward_range<_Rg>)
diff --git a/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/insert/insert_range.cc b/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/insert/insert_range.cc
index 4f48357..5c65610 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/insert/insert_range.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/bool/modifiers/insert/insert_range.cc
@@ -35,16 +35,22 @@ do_test()
   VERIFY( eq(v, a) );
   v.clear();
   v.shrink_to_fit();
-  v.insert_range(v.begin(), Range(a, a+3));
-  v.insert_range(v.end(), Range(a+6, a+9));
-  v.insert_range(v.begin()+3, Range(a+3, a+6));
+  auto it = v.insert_range(v.begin(), Range(a, a+3));
+  VERIFY( it == v.begin() );
+  it = v.insert_range(v.end(), Range(a+6, a+9));
+  VERIFY( it == v.begin()+3 );
+  it = v.insert_range(v.begin()+3, Range(a+3, a+6));
+  VERIFY( it == v.begin()+3 );
   VERIFY( eq(v, a) );
   v.resize(3);
-  v.insert_range(v.begin()+1, Range(a+4, a+9));
-  v.insert_range(v.begin()+1, Range(a+1, a+4));
+  it = v.insert_range(v.begin()+1, Range(a+4, a+9));
+  VERIFY( it == v.begin()+1 );
+  it = v.insert_range(v.begin()+1, Range(a+1, a+4));
+  VERIFY( it == v.begin()+1 );
   v.resize(9);
   VERIFY( eq(v, a) );
-  v.insert_range(v.begin(), Range(a, a));
+  it = v.insert_range(v.begin(), Range(a, a));
+  VERIFY( it == v.begin() );
   VERIFY( eq(v, a) );
 }
 
diff --git a/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/insert_range.cc b/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/insert_range.cc
index 68218e9..5907143 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/insert_range.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/insert_range.cc
@@ -39,16 +39,22 @@ do_test()
   VERIFY( eq(v, a) );
   v.clear();
   v.shrink_to_fit();
-  v.insert_range(v.begin(), Range(a, a+3));
-  v.insert_range(v.end(), Range(a+6, a+9));
-  v.insert_range(v.begin()+3, Range(a+3, a+6));
+  auto it = v.insert_range(v.begin(), Range(a, a+3));
+  VERIFY( it == v.begin() );
+  it = v.insert_range(v.end(), Range(a+6, a+9));
+  VERIFY( it == v.begin()+3 );
+  it = v.insert_range(v.begin()+3, Range(a+3, a+6));
+  VERIFY( it == v.begin()+3 );
   VERIFY( eq(v, a) );
   v.resize(3);
-  v.insert_range(v.begin()+1, Range(a+4, a+9));
-  v.insert_range(v.begin()+1, Range(a+1, a+4));
+  it = v.insert_range(v.begin()+1, Range(a+4, a+9));
+  VERIFY( it == v.begin()+1 );
+  it = v.insert_range(v.begin()+1, Range(a+1, a+4));
+  VERIFY( it == v.begin()+1 );
   v.resize(9);
   VERIFY( eq(v, a) );
-  v.insert_range(v.begin() + 6, Range(a, a));
+  it = v.insert_range(v.begin() + 6, Range(a, a));
+  VERIFY( it == v.begin() + 6 );
   VERIFY( eq(v, a) );
 }