Merge pull request #4018 from ethereum/disable-bytes0

Disable FixedBytesType(0) aka bytes0

libsolidity/ast/Types.cpp

@@ -1264,17 +1264,12 @@ bool StringLiteralType::isValidUTF8() const
 	return dev::validateUTF8(m_value);
 }
 
-shared_ptr<FixedBytesType> FixedBytesType::smallestTypeForLiteral(string const& _literal)
-{
-	if (_literal.length() <= 32)
-		return make_shared<FixedBytesType>(_literal.length());
-	return shared_ptr<FixedBytesType>();
-}
-
 FixedBytesType::FixedBytesType(int _bytes): m_bytes(_bytes)
 {
-	solAssert(m_bytes >= 0 && m_bytes <= 32,
+	solAssert(
-			  "Invalid byte number for fixed bytes type: " + dev::toString(m_bytes));
+		m_bytes > 0 && m_bytes <= 32,
+		"Invalid byte number for fixed bytes type: " + dev::toString(m_bytes)
+	);
 }
 
 bool FixedBytesType::isImplicitlyConvertibleTo(Type const& _convertTo) const

libsolidity/ast/Types.h

@@ -505,10 +505,6 @@ class FixedBytesType: public Type
 public:
 	virtual Category category() const override { return Category::FixedBytes; }
 
-	/// @returns the smallest bytes type for the given literal or an empty pointer
-	/// if no type fits.
-	static std::shared_ptr<FixedBytesType> smallestTypeForLiteral(std::string const& _literal);
-
 	explicit FixedBytesType(int _bytes);
 
 	virtual bool isImplicitlyConvertibleTo(Type const& _convertTo) const override;

test/libsolidity/syntaxTests/empty_string_var.sol

@@ -0,0 +1,11 @@
+contract C {
+  function f() {
+    var a = "";
+    bytes1 b = bytes1(a);
+    bytes memory c = bytes(a);
+    string memory d = string(a);
+  }
+}
+// ----
+// Warning: (34-39): Use of the "var" keyword is deprecated.
+// TypeError: (61-70): Explicit type conversion not allowed from "string memory" to "bytes1".

test/libsolidity/syntaxTests/types/bytes0.sol

@@ -0,0 +1,5 @@
+contract C {
+  bytes0 b0 = 1;
+}
+// ----
+// DeclarationError: (15-21): Identifier not found or not unique.

test/libsolidity/syntaxTests/types/bytes256.sol

@@ -0,0 +1,5 @@
+contract C {
+  bytes256 b256 = 1;
+}
+// ----
+// DeclarationError: (15-23): Identifier not found or not unique.

test/libsolidity/syntaxTests/types/bytes33.sol

@@ -0,0 +1,5 @@
+contract C {
+  bytes33 b33 = 1;
+}
+// ----
+// DeclarationError: (15-22): Identifier not found or not unique.

test/libsolidity/syntaxTests/types/bytesm.sol

@@ -0,0 +1,36 @@
+contract C {
+  byte b = byte(1);
+  bytes1 b1 = b;
+  bytes2 b2 = b1;
+  bytes3 b3 = b2;
+  bytes4 b4 = b3;
+  bytes5 b5 = b4;
+  bytes6 b6 = b5;
+  bytes7 b7 = b6;
+  bytes8 b8 = b7;
+  bytes9 b9 = b8;
+  bytes10 b10 = b9;
+  bytes11 b11 = b10;
+  bytes12 b12 = b11;
+  bytes13 b13 = b12;
+  bytes14 b14 = b13;
+  bytes15 b15 = b14;
+  bytes16 b16 = b15;
+  bytes17 b17 = b16;
+  bytes18 b18 = b17;
+  bytes19 b19 = b18;
+  bytes20 b20 = b19;
+  bytes21 b21 = b20;
+  bytes22 b22 = b21;
+  bytes23 b23 = b22;
+  bytes24 b24 = b23;
+  bytes25 b25 = b24;
+  bytes26 b26 = b25;
+  bytes27 b27 = b26;
+  bytes28 b28 = b27;
+  bytes29 b29 = b28;
+  bytes30 b30 = b29;
+  bytes31 b31 = b30;
+  bytes32 b32 = b31;
+}
+// ----