diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 7335ba548..42ff01213 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -1382,12 +1382,25 @@ bool StringLiteralType::operator==(Type const& _other) const
 
 std::string StringLiteralType::toString(bool) const
 {
+	auto isPrintableASCII = [](string const& s)
+	{
+		for (auto c: s)
+		{
+			if (static_cast<unsigned>(c) <= 0x1f || static_cast<unsigned>(c) >= 0x7f)
+				return false;
+		}
+		return true;
+	};
+
+	string ret = isPrintableASCII(m_value) ?
+		("literal_string \"" + m_value + "\"") :
+		("literal_string hex\"" + util::toHex(util::asBytes(m_value)) + "\"");
+
 	size_t invalidSequence;
-
 	if (!util::validateUTF8(m_value, invalidSequence))
-		return "literal_string (contains invalid UTF-8 sequence at position " + util::toString(invalidSequence) + ")";
+		ret += " (contains invalid UTF-8 sequence at position " + util::toString(invalidSequence) + ")";
 
-	return "literal_string \"" + m_value + "\"";
+	return ret;
 }
 
 TypePointer StringLiteralType::mobileType() const
diff --git a/test/libsolidity/ASTJSON/non_utf8.json b/test/libsolidity/ASTJSON/non_utf8.json
index 98db4273f..eab03546d 100644
--- a/test/libsolidity/ASTJSON/non_utf8.json
+++ b/test/libsolidity/ASTJSON/non_utf8.json
@@ -86,7 +86,7 @@
                   "typeDescriptions":
                   {
                     "typeIdentifier": "t_stringliteral_8b1a944cf13a9a1c08facb2c9e98623ef3254d2ddb48113885c3e8e97fec8db9",
-                    "typeString": "literal_string (contains invalid UTF-8 sequence at position 0)"
+                    "typeString": "literal_string hex\"ff\" (contains invalid UTF-8 sequence at position 0)"
                   }
                 },
                 "nodeType": "VariableDeclarationStatement",
diff --git a/test/libsolidity/ASTJSON/non_utf8_legacy.json b/test/libsolidity/ASTJSON/non_utf8_legacy.json
index d9430c82d..566d29c4b 100644
--- a/test/libsolidity/ASTJSON/non_utf8_legacy.json
+++ b/test/libsolidity/ASTJSON/non_utf8_legacy.json
@@ -131,7 +131,7 @@
                         "isPure": true,
                         "lValueRequested": false,
                         "token": "hexString",
-                        "type": "literal_string (contains invalid UTF-8 sequence at position 0)"
+                        "type": "literal_string hex\"ff\" (contains invalid UTF-8 sequence at position 0)"
                       },
                       "id": 5,
                       "name": "Literal",
diff --git a/test/libsolidity/ASTJSON/unicode.json b/test/libsolidity/ASTJSON/unicode.json
index 81c8ad0da..219d89500 100644
--- a/test/libsolidity/ASTJSON/unicode.json
+++ b/test/libsolidity/ASTJSON/unicode.json
@@ -86,7 +86,7 @@
                   "typeDescriptions":
                   {
                     "typeIdentifier": "t_stringliteral_cd7a99177cebb3d14b8cc54e313dbf76867c71cd6fbb9a33ce3870dc80e9992b",
-                    "typeString": "literal_string \"Hello \ud83d\ude03\""
+                    "typeString": "literal_string hex\"48656c6c6f20f09f9883\""
                   },
                   "value": "Hello \ud83d\ude03"
                 },
diff --git a/test/libsolidity/ASTJSON/unicode_legacy.json b/test/libsolidity/ASTJSON/unicode_legacy.json
index 22976f6f9..f3e4ad321 100644
--- a/test/libsolidity/ASTJSON/unicode_legacy.json
+++ b/test/libsolidity/ASTJSON/unicode_legacy.json
@@ -131,7 +131,7 @@
                         "isPure": true,
                         "lValueRequested": false,
                         "token": "unicodeString",
-                        "type": "literal_string \"Hello \ud83d\ude03\"",
+                        "type": "literal_string hex\"48656c6c6f20f09f9883\"",
                         "value": "Hello \ud83d\ude03"
                       },
                       "id": 5,
diff --git a/test/libsolidity/syntaxTests/string/invalid_utf8_explicit_string.sol b/test/libsolidity/syntaxTests/string/invalid_utf8_explicit_string.sol
index b9a8c5279..4084c99e9 100644
--- a/test/libsolidity/syntaxTests/string/invalid_utf8_explicit_string.sol
+++ b/test/libsolidity/syntaxTests/string/invalid_utf8_explicit_string.sol
@@ -2,4 +2,4 @@ contract C {
     string s = string("\xa0\x00");
 }
 // ----
-// TypeError 9640: (28-46): Explicit type conversion not allowed from "literal_string (contains invalid UTF-8 sequence at position 0)" to "string memory".
+// TypeError 9640: (28-46): Explicit type conversion not allowed from "literal_string hex"a000" (contains invalid UTF-8 sequence at position 0)" to "string memory".
diff --git a/test/libsolidity/syntaxTests/string/invalid_utf8_hex_string.sol b/test/libsolidity/syntaxTests/string/invalid_utf8_hex_string.sol
index d72ee5af0..d25886c91 100644
--- a/test/libsolidity/syntaxTests/string/invalid_utf8_hex_string.sol
+++ b/test/libsolidity/syntaxTests/string/invalid_utf8_hex_string.sol
@@ -2,4 +2,4 @@ contract C {
     string s = hex"a000";
 }
 // ----
-// TypeError 7407: (28-37): Type literal_string (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type string storage ref.
+// TypeError 7407: (28-37): Type literal_string hex"a000" (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type string storage ref.
diff --git a/test/libsolidity/syntaxTests/string/invalid_utf8_implicit_string.sol b/test/libsolidity/syntaxTests/string/invalid_utf8_implicit_string.sol
index 3cf3361f3..6b630249e 100644
--- a/test/libsolidity/syntaxTests/string/invalid_utf8_implicit_string.sol
+++ b/test/libsolidity/syntaxTests/string/invalid_utf8_implicit_string.sol
@@ -2,4 +2,4 @@ contract C {
     string s = "\xa0\x00";
 }
 // ----
-// TypeError 7407: (28-38): Type literal_string (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type string storage ref.
+// TypeError 7407: (28-38): Type literal_string hex"a000" (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type string storage ref.
diff --git a/test/libsolidity/syntaxTests/string/invalid_utf8_sequence.sol b/test/libsolidity/syntaxTests/string/invalid_utf8_sequence.sol
index 7655757a7..05b0f223c 100644
--- a/test/libsolidity/syntaxTests/string/invalid_utf8_sequence.sol
+++ b/test/libsolidity/syntaxTests/string/invalid_utf8_sequence.sol
@@ -3,4 +3,4 @@ contract C {
 }
 // ----
 // SyntaxError 8452: (28-38): Contains invalid UTF-8 sequence at position 0.
-// TypeError 7407: (28-38): Type literal_string (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type string storage ref.
+// TypeError 7407: (28-38): Type literal_string hex"c0" (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type string storage ref.
diff --git a/test/libsolidity/syntaxTests/string/unicode_escape_literals_invalid_codepoint.sol b/test/libsolidity/syntaxTests/string/unicode_escape_literals_invalid_codepoint.sol
index 46a0de5f4..f30f26fe4 100644
--- a/test/libsolidity/syntaxTests/string/unicode_escape_literals_invalid_codepoint.sol
+++ b/test/libsolidity/syntaxTests/string/unicode_escape_literals_invalid_codepoint.sol
@@ -4,4 +4,4 @@ contract test {
     }
 }
 // ----
-// TypeError 6359: (86-92): Return argument type literal_string (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type (type of first return variable) string memory.
+// TypeError 6359: (86-92): Return argument type literal_string hex"c1" (contains invalid UTF-8 sequence at position 0) is not implicitly convertible to expected type (type of first return variable) string memory.
diff --git a/test/libsolidity/syntaxTests/types/bytesNN_with_oversized_hex_string.sol b/test/libsolidity/syntaxTests/types/bytesNN_with_oversized_hex_string.sol
index a76c4ec53..9412a7882 100644
--- a/test/libsolidity/syntaxTests/types/bytesNN_with_oversized_hex_string.sol
+++ b/test/libsolidity/syntaxTests/types/bytesNN_with_oversized_hex_string.sol
@@ -4,4 +4,4 @@ contract C {
     }
 }
 // ----
-// TypeError 9640: (76-95): Explicit type conversion not allowed from "literal_string "4V"" to "bytes2". Literal is larger than the type.
+// TypeError 9640: (76-95): Explicit type conversion not allowed from "literal_string hex"123456"" to "bytes2". Literal is larger than the type.
diff --git a/test/libsolidity/syntaxTests/types/hex_string_to_bytesNN_different_size_explicit.sol b/test/libsolidity/syntaxTests/types/hex_string_to_bytesNN_different_size_explicit.sol
index 829199bf2..3fa37ddf1 100644
--- a/test/libsolidity/syntaxTests/types/hex_string_to_bytesNN_different_size_explicit.sol
+++ b/test/libsolidity/syntaxTests/types/hex_string_to_bytesNN_different_size_explicit.sol
@@ -14,7 +14,7 @@ contract C {
    }
 }
 // ----
-// TypeError 9640: (92-109): Explicit type conversion not allowed from "literal_string "4"" to "bytes1". Literal is larger than the type.
-// TypeError 9640: (198-217): Explicit type conversion not allowed from "literal_string "4V"" to "bytes2". Literal is larger than the type.
-// TypeError 9640: (310-331): Explicit type conversion not allowed from "literal_string "4Vx"" to "bytes3". Literal is larger than the type.
-// TypeError 9640: (430-453): Explicit type conversion not allowed from "literal_string (contains invalid UTF-8 sequence at position 4)" to "bytes4". Literal is larger than the type.
+// TypeError 9640: (92-109): Explicit type conversion not allowed from "literal_string hex"1234"" to "bytes1". Literal is larger than the type.
+// TypeError 9640: (198-217): Explicit type conversion not allowed from "literal_string hex"123456"" to "bytes2". Literal is larger than the type.
+// TypeError 9640: (310-331): Explicit type conversion not allowed from "literal_string hex"12345678"" to "bytes3". Literal is larger than the type.
+// TypeError 9640: (430-453): Explicit type conversion not allowed from "literal_string hex"1234567890" (contains invalid UTF-8 sequence at position 4)" to "bytes4". Literal is larger than the type.