"Operator has not been user-defined." is displayed only is operator can be user-defined

libsolidity/CMakeLists.txt

@@ -63,6 +63,7 @@ set(sources
 	ast/CallGraph.cpp
 	ast/CallGraph.h
 	ast/ExperimentalFeatures.h
+	ast/OverridableOperators.h
 	ast/Types.cpp
 	ast/Types.h
 	ast/TypeProvider.cpp

libsolidity/ast/OverridableOperators.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <liblangutil/Token.h>
+
+#include <vector>
+
+namespace solidity::frontend
+{
+
+std::vector<langutil::Token> const overridableOperators = {
+	langutil::Token::BitOr,
+	langutil::Token::BitAnd,
+	langutil::Token::BitXor,
+	langutil::Token::Add,
+	langutil::Token::Sub,
+	langutil::Token::Mul,
+	langutil::Token::Div,
+	langutil::Token::Mod,
+	langutil::Token::Equal,
+	langutil::Token::NotEqual,
+	langutil::Token::LessThan,
+	langutil::Token::GreaterThan,
+	langutil::Token::LessThanOrEqual,
+	langutil::Token::GreaterThanOrEqual,
+	langutil::Token::BitNot,
+	langutil::Token::SHL,
+	langutil::Token::SAR,
+	langutil::Token::Exp,
+	langutil::Token::Not
+};
+
+}

libsolidity/ast/Types.cpp

@@ -25,6 +25,7 @@
 
 #include <libsolidity/ast/AST.h>
 #include <libsolidity/ast/TypeProvider.h>
+#include <libsolidity/ast/OverridableOperators.h>
 
 #include <libsolidity/analysis/ConstantEvaluator.h>
 
@@ -387,7 +388,7 @@ vector<UsingForDirective const*> usingForDirectivesForType(Type const& _type, AS
 
 Result<FunctionDefinition const*> Type::userDefinedOperator(Token _token, ASTNode const& _scope, bool _unaryOperation) const
 {
-	if (!typeDefinition())
+	if (!typeDefinition() || !util::contains(overridableOperators, _token))
 		return nullptr;
 
 	set<FunctionDefinition const*> matchingDefinitions;

libsolidity/parsing/Parser.cpp

@@ -23,6 +23,7 @@
 
 #include <libsolidity/parsing/Parser.h>
 
+#include <libsolidity/ast/OverridableOperators.h>
 #include <libsolidity/interface/Version.h>
 #include <libyul/AST.h>
 #include <libyul/AsmParser.h>
@@ -980,13 +981,6 @@ ASTPointer<UsingForDirective> Parser::parseUsingDirective()
 			{
 				advance();
 				Token operator_ = m_scanner->currentToken();
-				vector<Token> static const overridableOperators = {
-					Token::BitOr, Token::BitAnd, Token::BitXor,
-					Token::Add, Token::Sub, Token::Mul, Token::Div, Token::Mod,
-					Token::Equal, Token::NotEqual,
-					Token::LessThan, Token::GreaterThan, Token::LessThanOrEqual, Token::GreaterThanOrEqual,
-					Token::BitNot, Token::SHL, Token::SAR, Token::Exp, Token::Not
-				};
 				if (!util::contains(overridableOperators, operator_))
 				{
 					parserError(

test/libsolidity/syntaxTests/operators/custom/binary_operator_cannot_be_applied.sol

@@ -0,0 +1,11 @@
+type Int is int256;
+
+function f() pure {
+    Int a = Int.wrap(0);
+    a + a;
+    a >>> a;
+}
+
+// ----
+// TypeError 2271: (70-75): Binary operator + not compatible with types Int and Int. No matching user-defined operator found.
+// TypeError 2271: (81-88): Binary operator >>> not compatible with types Int and Int.

test/libsolidity/syntaxTests/operators/custom/unary_operator_cannot_be_applied.sol

@@ -0,0 +1,11 @@
+type Int is int256;
+
+function f() pure {
+    Int a = Int.wrap(0);
+    -a;
+    a++;
+}
+
+// ----
+// TypeError 4907: (70-72): Unary operator - cannot be applied to type Int. No matching user-defined operator found.
+// TypeError 9767: (78-81): Unary operator ++ cannot be applied to type Int.