Adds syntax tests, documentation and changelog entry.

Refines comment for array utility function.

33 files changed, 61 insertions, 3 deletions

diff --git a/Changelog.md b/Changelog.md
index c31aced2..a1248868 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,5 +1,7 @@
 ### 0.5.0 (unreleased)
 
+Language Features:
+ * General: Support ``pop()`` for storage arrays.
 
 Breaking Changes:
  * Disallow conversions between bytesX and uintY of different size.
diff --git a/docs/types.rst b/docs/types.rst
index 794a70de..b3631f74 100644
--- a/docs/types.rst
+++ b/docs/types.rst
@@ -682,7 +682,7 @@ possible:
 It is planned to remove this restriction in the future but currently creates
 some complications because of how arrays are passed in the ABI.
 
-.. index:: ! array;length, length, push, !array;push
+.. index:: ! array;length, length, push, pop, !array;push, !array;pop
 
 Members
 ^^^^^^^
@@ -693,6 +693,8 @@ Members
     ``.length`` member. This does not happen automatically when attempting to access elements outside the current length. The size of memory arrays is fixed (but dynamic, i.e. it can depend on runtime parameters) once they are created.
 **push**:
      Dynamic storage arrays and ``bytes`` (not ``string``) have a member function called ``push`` that can be used to append an element at the end of the array. The function returns the new length.
+**pop**:
+     Dynamic storage arrays and ``bytes`` (not ``string``) have a member function called ``pop`` that can be used to remove an element from the end of the array.
 
 .. warning::
     It is not yet possible to use arrays of arrays in external functions.
diff --git a/libsolidity/codegen/ArrayUtils.cpp b/libsolidity/codegen/ArrayUtils.cpp
index d78e64a9..6bb9a961 100644
--- a/libsolidity/codegen/ArrayUtils.cpp
+++ b/libsolidity/codegen/ArrayUtils.cpp
@@ -840,7 +840,7 @@ void ArrayUtils::popStorageArrayElement(ArrayType const& _type) const
 				let length := and(div(slot_value, 2), 0x1f)
 				if iszero(length) { invalid() }
 
-				// Zero-out the suffix inlcluding the least significant byte.
+				// Zero-out the suffix including the least significant byte.
 				let mask := sub(exp(0x100, sub(33, length)), 1)
 				length := sub(length, 1)
 				slot_value := or(and(not(mask), slot_value), mul(length, 2))
diff --git a/libsolidity/codegen/ArrayUtils.h b/libsolidity/codegen/ArrayUtils.h
index 84d591d7..daf50bf5 100644
--- a/libsolidity/codegen/ArrayUtils.h
+++ b/libsolidity/codegen/ArrayUtils.h
@@ -73,7 +73,7 @@ public:
 	/// Stack pre: reference (excludes byte offset)
 	/// Stack post: new_length
 	void incrementDynamicArraySize(ArrayType const& _type) const;
-	/// Decrements the size of a dynamic array by one if length is nonzero. Returns otherwise.
+	/// Decrements the size of a dynamic array by one if length is nonzero. Causes an invalid instruction otherwise.
 	/// Clears the removed data element. In case of a byte array, this might move the data.
 	/// Stack pre: reference
 	/// Stack post:
diff --git a/test/libsolidity/syntaxTests/array/array_pop.sol b/test/libsolidity/syntaxTests/array/array_pop.sol
new file mode 100644
index 00000000..3804f911
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/array_pop.sol
@@ -0,0 +1,7 @@
+contract C {
+    uint[] data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
diff --git a/test/libsolidity/syntaxTests/array/array_pop_arg.sol b/test/libsolidity/syntaxTests/array/array_pop_arg.sol
new file mode 100644
index 00000000..bb7803e2
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/array_pop_arg.sol
@@ -0,0 +1,8 @@
+contract C {
+    uint[] data;
+    function test() public {
+      data.pop(5);
+    }
+}
+// ----
+// TypeError: (65-76): Wrong argument count for function call: 1 arguments given but expected 0.
diff --git a/test/libsolidity/syntaxTests/array/bytes_pop.sol b/test/libsolidity/syntaxTests/array/bytes_pop.sol
new file mode 100644
index 00000000..cd5aa0eb
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/bytes_pop.sol
@@ -0,0 +1,7 @@
+contract C {
+    bytes data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
diff --git a/test/libsolidity/syntaxTests/array/dynamic_memory_array_pop.sol b/test/libsolidity/syntaxTests/array/dynamic_memory_array_pop.sol
new file mode 100644
index 00000000..5a79afc9
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/dynamic_memory_array_pop.sol
@@ -0,0 +1,8 @@
+contract C {
+    function test() public {
+      uint[] memory data;
+      data.pop();
+    }
+}
+// ----
+// TypeError: (74-82): Member "pop" is not available in uint256[] memory outside of storage.
diff --git a/test/libsolidity/syntaxTests/arrayLength/array_length_cannot_be_constant_function_parameter.sol b/test/libsolidity/syntaxTests/array/length/array_length_cannot_be_constant_function_parameter.sol
index 11d40f26..11d40f26 100644
--- a/test/libsolidity/syntaxTests/arrayLength/array_length_cannot_be_constant_function_parameter.sol
+++ b/test/libsolidity/syntaxTests/array/length/array_length_cannot_be_constant_function_parameter.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/can_be_constant_in_function.sol b/test/libsolidity/syntaxTests/array/length/can_be_constant_in_function.sol
index 92536dd5..92536dd5 100644
--- a/test/libsolidity/syntaxTests/arrayLength/can_be_constant_in_function.sol
+++ b/test/libsolidity/syntaxTests/array/length/can_be_constant_in_function.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/can_be_constant_in_struct.sol b/test/libsolidity/syntaxTests/array/length/can_be_constant_in_struct.sol
index 89e174f2..89e174f2 100644
--- a/test/libsolidity/syntaxTests/arrayLength/can_be_constant_in_struct.sol
+++ b/test/libsolidity/syntaxTests/array/length/can_be_constant_in_struct.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/can_be_recursive_constant.sol b/test/libsolidity/syntaxTests/array/length/can_be_recursive_constant.sol
index 6810a9d6..6810a9d6 100644
--- a/test/libsolidity/syntaxTests/arrayLength/can_be_recursive_constant.sol
+++ b/test/libsolidity/syntaxTests/array/length/can_be_recursive_constant.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/cannot_be_function.sol b/test/libsolidity/syntaxTests/array/length/cannot_be_function.sol
index ac3abc4c..ac3abc4c 100644
--- a/test/libsolidity/syntaxTests/arrayLength/cannot_be_function.sol
+++ b/test/libsolidity/syntaxTests/array/length/cannot_be_function.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/cannot_be_function_call.sol b/test/libsolidity/syntaxTests/array/length/cannot_be_function_call.sol
index a6863955..a6863955 100644
--- a/test/libsolidity/syntaxTests/arrayLength/cannot_be_function_call.sol
+++ b/test/libsolidity/syntaxTests/array/length/cannot_be_function_call.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/complex_cyclic_constant.sol b/test/libsolidity/syntaxTests/array/length/complex_cyclic_constant.sol
index 254f9f02..254f9f02 100644
--- a/test/libsolidity/syntaxTests/arrayLength/complex_cyclic_constant.sol
+++ b/test/libsolidity/syntaxTests/array/length/complex_cyclic_constant.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/const_cannot_be_fractional.sol b/test/libsolidity/syntaxTests/array/length/const_cannot_be_fractional.sol
index 397bbbcd..397bbbcd 100644
--- a/test/libsolidity/syntaxTests/arrayLength/const_cannot_be_fractional.sol
+++ b/test/libsolidity/syntaxTests/array/length/const_cannot_be_fractional.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/constant_var.sol b/test/libsolidity/syntaxTests/array/length/constant_var.sol
index 41750250..41750250 100644
--- a/test/libsolidity/syntaxTests/arrayLength/constant_var.sol
+++ b/test/libsolidity/syntaxTests/array/length/constant_var.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/cyclic_constant.sol b/test/libsolidity/syntaxTests/array/length/cyclic_constant.sol
index 91ba9045..91ba9045 100644
--- a/test/libsolidity/syntaxTests/arrayLength/cyclic_constant.sol
+++ b/test/libsolidity/syntaxTests/array/length/cyclic_constant.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/inline_array.sol b/test/libsolidity/syntaxTests/array/length/inline_array.sol
index a30745d3..a30745d3 100644
--- a/test/libsolidity/syntaxTests/arrayLength/inline_array.sol
+++ b/test/libsolidity/syntaxTests/array/length/inline_array.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_1.sol b/test/libsolidity/syntaxTests/array/length/invalid_expression_1.sol
index c92861eb..c92861eb 100644
--- a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_1.sol
+++ b/test/libsolidity/syntaxTests/array/length/invalid_expression_1.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_2.sol b/test/libsolidity/syntaxTests/array/length/invalid_expression_2.sol
index 92e3c3cf..92e3c3cf 100644
--- a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_2.sol
+++ b/test/libsolidity/syntaxTests/array/length/invalid_expression_2.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_3.sol b/test/libsolidity/syntaxTests/array/length/invalid_expression_3.sol
index 26add45c..26add45c 100644
--- a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_3.sol
+++ b/test/libsolidity/syntaxTests/array/length/invalid_expression_3.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_4.sol b/test/libsolidity/syntaxTests/array/length/invalid_expression_4.sol
index a0d58f4a..a0d58f4a 100644
--- a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_4.sol
+++ b/test/libsolidity/syntaxTests/array/length/invalid_expression_4.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_5.sol b/test/libsolidity/syntaxTests/array/length/invalid_expression_5.sol
index 38a80867..38a80867 100644
--- a/test/libsolidity/syntaxTests/arrayLength/invalid_expression_5.sol
+++ b/test/libsolidity/syntaxTests/array/length/invalid_expression_5.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/non_integer_constant_var.sol b/test/libsolidity/syntaxTests/array/length/non_integer_constant_var.sol
index 7a853a34..7a853a34 100644
--- a/test/libsolidity/syntaxTests/arrayLength/non_integer_constant_var.sol
+++ b/test/libsolidity/syntaxTests/array/length/non_integer_constant_var.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/not_convertible_to_integer.sol b/test/libsolidity/syntaxTests/array/length/not_convertible_to_integer.sol
index b44ccfe9..b44ccfe9 100644
--- a/test/libsolidity/syntaxTests/arrayLength/not_convertible_to_integer.sol
+++ b/test/libsolidity/syntaxTests/array/length/not_convertible_to_integer.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/parentheses.sol b/test/libsolidity/syntaxTests/array/length/parentheses.sol
index 40f55ad6..40f55ad6 100644
--- a/test/libsolidity/syntaxTests/arrayLength/parentheses.sol
+++ b/test/libsolidity/syntaxTests/array/length/parentheses.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/pure_functions.sol b/test/libsolidity/syntaxTests/array/length/pure_functions.sol
index b620db76..b620db76 100644
--- a/test/libsolidity/syntaxTests/arrayLength/pure_functions.sol
+++ b/test/libsolidity/syntaxTests/array/length/pure_functions.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/too_large.sol b/test/libsolidity/syntaxTests/array/length/too_large.sol
index c90a7494..c90a7494 100644
--- a/test/libsolidity/syntaxTests/arrayLength/too_large.sol
+++ b/test/libsolidity/syntaxTests/array/length/too_large.sol
diff --git a/test/libsolidity/syntaxTests/arrayLength/tuples.sol b/test/libsolidity/syntaxTests/array/length/tuples.sol
index bc10b3b5..bc10b3b5 100644
--- a/test/libsolidity/syntaxTests/arrayLength/tuples.sol
+++ b/test/libsolidity/syntaxTests/array/length/tuples.sol
diff --git a/test/libsolidity/syntaxTests/array/no_array_pop.sol b/test/libsolidity/syntaxTests/array/no_array_pop.sol
new file mode 100644
index 00000000..44e54ad2
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/no_array_pop.sol
@@ -0,0 +1,8 @@
+contract C {
+    uint data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
+// TypeError: (63-71): Member "pop" not found or not visible after argument-dependent lookup in uint256
diff --git a/test/libsolidity/syntaxTests/array/static_storage_array_pop.sol b/test/libsolidity/syntaxTests/array/static_storage_array_pop.sol
new file mode 100644
index 00000000..0af171ad
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/static_storage_array_pop.sol
@@ -0,0 +1,8 @@
+contract C {
+    uint[3] data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
+// TypeError: (66-74): Member "pop" not found or not visible after argument-dependent lookup in uint256[3] storage ref
diff --git a/test/libsolidity/syntaxTests/array/string_pop.sol b/test/libsolidity/syntaxTests/array/string_pop.sol
new file mode 100644
index 00000000..2a46d0c3
--- /dev/null
+++ b/test/libsolidity/syntaxTests/array/string_pop.sol
@@ -0,0 +1,8 @@
+contract C {
+    string data;
+    function test() public {
+      data.pop();
+    }
+}
+// ----
+// TypeError: (65-73): Member "pop" not found or not visible after argument-dependent lookup in string storage ref