Merge pull request #4056 from ethereum/safetupleassignment

Deprecate wildcard assignments.

11 files changed, 114 insertions, 75 deletions

diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index a2540302..91fd1fff 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -2894,7 +2894,7 @@ BOOST_AUTO_TEST_CASE(dynamic_return_types_not_possible)
 		contract C {
 			function f(uint) public returns (string);
 			function g() public {
-				var (x,) = this.f(2);
+				var x = this.f(2);
 				// we can assign to x but it is not usable.
 				bytes(x).length;
 			}
@@ -5833,80 +5833,6 @@ BOOST_AUTO_TEST_CASE(pure_statement_check_for_regular_for_loop)
 	CHECK_SUCCESS(text);
 }
 
-BOOST_AUTO_TEST_CASE(warn_multiple_storage_storage_copies)
-{
-	char const* text = R"(
-		contract C {
-			struct S { uint a; uint b; }
-			S x; S y;
-			function f() public {
-				(x, y) = (y, x);
-			}
-		}
-	)";
-	CHECK_WARNING(text, "This assignment performs two copies to storage.");
-}
-
-BOOST_AUTO_TEST_CASE(warn_multiple_storage_storage_copies_fill_right)
-{
-	char const* text = R"(
-		contract C {
-			struct S { uint a; uint b; }
-			S x; S y;
-			function f() public {
-				(x, y, ) = (y, x, 1, 2);
-			}
-		}
-	)";
-	CHECK_WARNING(text, "This assignment performs two copies to storage.");
-}
-
-BOOST_AUTO_TEST_CASE(warn_multiple_storage_storage_copies_fill_left)
-{
-	char const* text = R"(
-		contract C {
-			struct S { uint a; uint b; }
-			S x; S y;
-			function f() public {
-				(,x, y) = (1, 2, y, x);
-			}
-		}
-	)";
-	CHECK_WARNING(text, "This assignment performs two copies to storage.");
-}
-
-BOOST_AUTO_TEST_CASE(nowarn_swap_memory)
-{
-	char const* text = R"(
-		contract C {
-			struct S { uint a; uint b; }
-			function f() pure public {
-				S memory x;
-				S memory y;
-				(x, y) = (y, x);
-			}
-		}
-	)";
-	CHECK_SUCCESS_NO_WARNINGS(text);
-}
-
-BOOST_AUTO_TEST_CASE(nowarn_swap_storage_pointers)
-{
-	char const* text = R"(
-		contract C {
-			struct S { uint a; uint b; }
-			S x; S y;
-			function f() public {
-				S storage x_local = x;
-				S storage y_local = y;
-				S storage z_local = x;
-				(x, y_local, x_local, z_local) = (y, x_local, y_local, y);
-			}
-		}
-	)";
-	CHECK_SUCCESS_NO_WARNINGS(text);
-}
-
 BOOST_AUTO_TEST_CASE(warn_unused_local)
 {
 	char const* text = R"(
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/error_fill.sol b/test/libsolidity/syntaxTests/tupleAssignments/error_fill.sol
new file mode 100644
index 00000000..5b7f870b
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/error_fill.sol
@@ -0,0 +1,12 @@
+pragma experimental "v0.5.0";
+contract C {
+	function f() public pure returns (uint, uint, bytes32) {
+		uint a;
+		bytes32 b;
+		(a,) = f();
+		(,b) = f();
+	}
+}
+// ----
+// TypeError: (126-136): Different number of components on the left hand side (2) than on the right hand side (3).
+// TypeError: (140-150): Different number of components on the left hand side (2) than on the right hand side (3).
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/large_component_count.sol b/test/libsolidity/syntaxTests/tupleAssignments/large_component_count.sol
new file mode 100644
index 00000000..bbf21d7e
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/large_component_count.sol
@@ -0,0 +1,24 @@
+pragma experimental "v0.5.0";
+contract C {
+	function g() public pure returns (
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint,
+		uint
+	) { }
+	function f() public pure returns (uint, uint, bytes32) {
+		uint a;
+		uint b;
+		(,,,,a,,,,b,,,,) = g();
+	}
+}
+// ----
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/nowarn_explicit_singleton_token_expression.sol b/test/libsolidity/syntaxTests/tupleAssignments/nowarn_explicit_singleton_token_expression.sol
new file mode 100644
index 00000000..3262781b
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/nowarn_explicit_singleton_token_expression.sol
@@ -0,0 +1,8 @@
+contract C {
+	function f() public pure {
+		uint a;
+		(a,) = (uint(1),);
+	}
+}
+// ----
+// Warning: (53-70): Different number of components on the left hand side (2) than on the right hand side (1).
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/nowarn_swap_memory.sol b/test/libsolidity/syntaxTests/tupleAssignments/nowarn_swap_memory.sol
new file mode 100644
index 00000000..b20bbf90
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/nowarn_swap_memory.sol
@@ -0,0 +1,8 @@
+contract C {
+	struct S { uint a; uint b; }
+	function f() pure public {
+		S memory x;
+		S memory y;
+		(x, y) = (y, x);
+	}
+}
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/nowarn_swap_storage_pointers.sol b/test/libsolidity/syntaxTests/tupleAssignments/nowarn_swap_storage_pointers.sol
new file mode 100644
index 00000000..5f7a18f7
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/nowarn_swap_storage_pointers.sol
@@ -0,0 +1,10 @@
+		contract C {
+			struct S { uint a; uint b; }
+			S x; S y;
+			function f() public {
+				S storage x_local = x;
+				S storage y_local = y;
+				S storage z_local = x;
+				(x, y_local, x_local, z_local) = (y, x_local, y_local, y);
+			}
+		}
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_assignment.sol b/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_assignment.sol
new file mode 100644
index 00000000..a079a509
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_assignment.sol
@@ -0,0 +1,11 @@
+contract C {
+	function f() public pure returns (uint, uint, bytes32) {
+		uint a;
+		bytes32 b;
+		(a,) = f();
+		(,b) = f();
+	}
+}
+// ----
+// Warning: (96-106): Different number of components on the left hand side (2) than on the right hand side (3).
+// Warning: (110-120): Different number of components on the left hand side (2) than on the right hand side (3).
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_vardecl.sol b/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_vardecl.sol
new file mode 100644
index 00000000..1d243c7c
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/warn_fill_vardecl.sol
@@ -0,0 +1,11 @@
+contract C {
+	function f() public pure returns (uint, uint, uint, uint) {
+		// Can later be replaced by (uint a, uint b,) = f();
+		var (a,b,) = f();
+		a; b;
+	}
+}
+// ----
+// Warning: (136-137): Use of the "var" keyword is deprecated.
+// Warning: (138-139): Use of the "var" keyword is deprecated.
+// Warning: (131-147): Different number of components on the left hand side (3) than on the right hand side (4).
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies.sol b/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies.sol
new file mode 100644
index 00000000..e4c3e694
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies.sol
@@ -0,0 +1,9 @@
+contract C {
+	struct S { uint a; uint b; }
+	S x; S y;
+	function f() public {
+		(x, y) = (y, x);
+	}
+}
+// ----
+// Warning: (79-94): This assignment performs two copies to storage. Since storage copies do not first copy to a temporary location, one of them might be overwritten before the second is executed and thus may have unexpected effects. It is safer to perform the copies separately or assign to storage pointers first.
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies_fill_left.sol b/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies_fill_left.sol
new file mode 100644
index 00000000..b2979804
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies_fill_left.sol
@@ -0,0 +1,10 @@
+contract C {
+	struct S { uint a; uint b; }
+	S x; S y;
+	function f() public {
+		(,x, y) = (1, 2, y, x);
+	}
+}
+// ----
+// Warning: (79-101): This assignment performs two copies to storage. Since storage copies do not first copy to a temporary location, one of them might be overwritten before the second is executed and thus may have unexpected effects. It is safer to perform the copies separately or assign to storage pointers first.
+// Warning: (79-101): Different number of components on the left hand side (3) than on the right hand side (4).
diff --git a/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies_fill_right.sol b/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies_fill_right.sol
new file mode 100644
index 00000000..aa35d7d4
--- /dev/null
+++ b/test/libsolidity/syntaxTests/tupleAssignments/warn_multiple_storage_storage_copies_fill_right.sol
@@ -0,0 +1,10 @@
+contract C {
+	struct S { uint a; uint b; }
+	S x; S y;
+	function f() public {
+		(x, y, ) = (y, x, 1, 2);
+	}
+}
+// ----
+// Warning: (79-102): This assignment performs two copies to storage. Since storage copies do not first copy to a temporary location, one of them might be overwritten before the second is executed and thus may have unexpected effects. It is safer to perform the copies separately or assign to storage pointers first.
+// Warning: (79-102): Different number of components on the left hand side (3) than on the right hand side (4).