Allow mapping arguments and return values in all internal functions.

Changelog.md

@@ -71,7 +71,7 @@ Language Features:
  * General: Support ``pop()`` for storage arrays.
  * General: Scoping rules now follow the C99-style.
  * General: Allow ``enum``s in interfaces.
- * General: Allow ``mapping`` arguments and return values in internal library functions.
+ * General: Allow ``mapping`` storage pointers as arguments and return values in all internal functions.
 
 Compiler Features:
  * C API (``libsolc``): Export the ``solidity_license``, ``solidity_version`` and ``solidity_compile`` methods.

libsolidity/analysis/TypeChecker.cpp

@@ -632,7 +632,6 @@ bool TypeChecker::visit(FunctionDefinition const& _function)
 		if (
 			!type(*var)->canLiveOutsideStorage() &&
 			!(
-				isLibraryFunction &&
 				(_function.visibility() <= FunctionDefinition::Visibility::Internal) &&
 				type(*var)->category() == Type::Category::Mapping
 			)

test/libsolidity/SolidityEndToEndTest.cpp

@@ -1543,6 +1543,62 @@ BOOST_AUTO_TEST_CASE(mapping_local_compound_assignment)
 	ABI_CHECK(callContractFunction("f()"), encodeArgs(byte(42), byte(0), byte(0), byte(21)));
 }
 
+BOOST_AUTO_TEST_CASE(mapping_internal_argument)
+{
+	char const* sourceCode = R"(
+		contract test {
+			mapping(uint8 => uint8) a;
+			mapping(uint8 => uint8) b;
+			function set_internal(mapping(uint8 => uint8) storage m, uint8 key, uint8 value) internal returns (uint8) {
+				uint8 oldValue = m[key];
+				m[key] = value;
+				return oldValue;
+			}
+			function set(uint8 key, uint8 value_a, uint8 value_b) public returns (uint8 old_a, uint8 old_b) {
+				old_a = set_internal(a, key, value_a);
+				old_b = set_internal(b, key, value_b);
+			}
+			function get(uint8 key) public returns (uint8, uint8) {
+				return (a[key], b[key]);
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+
+	ABI_CHECK(callContractFunction("set(uint8,uint8,uint8)", byte(1), byte(21), byte(42)), encodeArgs(byte(0), byte(0)));
+	ABI_CHECK(callContractFunction("get(uint8)", byte(1)), encodeArgs(byte(21), byte(42)));
+	ABI_CHECK(callContractFunction("set(uint8,uint8,uint8)", byte(1), byte(10), byte(11)), encodeArgs(byte(21), byte(42)));
+	ABI_CHECK(callContractFunction("get(uint8)", byte(1)), encodeArgs(byte(10), byte(11)));
+}
+
+BOOST_AUTO_TEST_CASE(mapping_internal_return)
+{
+	char const* sourceCode = R"(
+		contract test {
+			mapping(uint8 => uint8) a;
+			mapping(uint8 => uint8) b;
+			function f() internal returns (mapping(uint8 => uint8) storage r) {
+				r = a;
+				r[1] = 42;
+				r = b;
+				r[1] = 84;
+			}
+			function g() public returns (uint8, uint8, uint8, uint8, uint8, uint8) {
+				f()[2] = 21;
+				return (a[0], a[1], a[2], b[0], b[1], b[2]);
+			}
+			function h() public returns (uint8, uint8, uint8, uint8, uint8, uint8) {
+				mapping(uint8 => uint8) storage m = f();
+				m[2] = 17;
+				return (a[0], a[1], a[2], b[0], b[1], b[2]);
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+
+	ABI_CHECK(callContractFunction("g()"), encodeArgs(byte(0), byte(42), byte(0), byte(0), byte(84), byte (21)));
+	ABI_CHECK(callContractFunction("h()"), encodeArgs(byte(0), byte(42), byte(0), byte(0), byte(84), byte (17)));
+}
 
 BOOST_AUTO_TEST_CASE(structs)
 {

test/libsolidity/syntaxTests/types/mapping/argument_internal.sol

@@ -1,7 +1,5 @@
-// This is expected to fail now, but may work in the future.
 contract C {
     function f(mapping(uint => uint) storage) internal pure {
     }
 }
 // ----
-// TypeError: (89-110): Type is required to live outside storage.

test/libsolidity/syntaxTests/types/mapping/argument_private.sol

@@ -1,7 +1,5 @@
-// This is expected to fail now, but may work in the future.
 contract C {
     function f(mapping(uint => uint) storage) private pure {
     }
 }
 // ----
-// TypeError: (89-110): Type is required to live outside storage.

test/libsolidity/syntaxTests/types/mapping/mapping_return_internal.sol

@@ -1,4 +1,3 @@
-// This should be allowed in a future release.
 contract C {
     mapping(uint=>uint) m;
     function f() internal view returns (mapping(uint=>uint) storage) {
@@ -15,7 +14,3 @@ contract C {
     }
 }
 // ----
-// TypeError: (127-146): Type is required to live outside storage.
-// TypeError: (221-240): Type is required to live outside storage.
-// TypeError: (316-345): Type is required to live outside storage.
-// TypeError: (409-438): Type is required to live outside storage.