diff --git a/Changelog.md b/Changelog.md
index 7b19d37c0..06a761e6e 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -30,6 +30,7 @@ Bugfixes:
  * SMTChecker: Fix false negative when a verification target can be violated only by trusted external call from another public function.
  * SMTChecker: Fix internal error caused by using external identifier to encode member access to functions that take an internal function as a parameter.
  * Standard JSON Interface: Fix an incomplete AST being returned when analysis is interrupted by certain kinds of fatal errors.
+ * Type Checker: Disallow using certain unassignable function types in complex expressions.
  * Type Checker: Function declaration types referring to different declarations are no longer convertible to each other.
  * Yul Optimizer: Ensure that the assignment of memory slots for variables moved to memory does not depend on AST IDs that may depend on whether additional files are included during compilation.
  * Yul Optimizer: Fix ``FullInliner`` step not ignoring code that is not in expression-split form.
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 915440caa..47e1fea04 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -3472,7 +3472,11 @@ Type const* FunctionType::mobileType() const
 	if (valueSet() || gasSet() || saltSet() || hasBoundFirstArgument())
 		return nullptr;
 
-	// return function without parameter names
+	// Special function types do not get a mobile type, such that they cannot be used in complex expressions.
+	if (m_kind != FunctionType::Kind::Internal && m_kind != FunctionType::Kind::External && m_kind != FunctionType::Kind::DelegateCall)
+		return nullptr;
+
+	// return function without parameter names and without declaration
 	return TypeProvider::function(
 		m_parameterTypes,
 		m_returnParameterTypes,
@@ -3480,7 +3484,7 @@ Type const* FunctionType::mobileType() const
 		strings(m_returnParameterNames.size()),
 		m_kind,
 		m_stateMutability,
-		m_declaration,
+		nullptr,
 		Options::fromFunctionType(*this)
 	);
 }
diff --git a/test/libsolidity/semanticTests/functionTypes/selector_ternary.sol b/test/libsolidity/semanticTests/functionTypes/selector_ternary.sol
new file mode 100644
index 000000000..567b7c14b
--- /dev/null
+++ b/test/libsolidity/semanticTests/functionTypes/selector_ternary.sol
@@ -0,0 +1,10 @@
+contract C {
+	function f() public {}
+	function g() public {}
+	function h(bool c) public returns (bytes4) {
+		return (c ? this.f : this.g).selector;
+	}
+}
+// ----
+// h(bool): true -> 0x26121ff000000000000000000000000000000000000000000000000000000000
+// h(bool): false -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
diff --git a/test/libsolidity/semanticTests/functionTypes/selector_ternary_function_pointer_from_function_call.sol b/test/libsolidity/semanticTests/functionTypes/selector_ternary_function_pointer_from_function_call.sol
new file mode 100644
index 000000000..83415f728
--- /dev/null
+++ b/test/libsolidity/semanticTests/functionTypes/selector_ternary_function_pointer_from_function_call.sol
@@ -0,0 +1,19 @@
+contract A {
+    function f() public {}
+	function g() public {}
+}
+
+contract C {
+    A a = new A();
+
+    function getContract() public view returns (A) {
+        return a;
+    }
+
+    function test(bool b) public view returns (bytes4) {
+        return (b ? getContract().f : getContract().g).selector;
+    }
+}
+// ----
+// test(bool): true -> 0x26121ff000000000000000000000000000000000000000000000000000000000
+// test(bool): false -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
diff --git a/test/libsolidity/semanticTests/functionTypes/ternary_contract_internal_function.sol b/test/libsolidity/semanticTests/functionTypes/ternary_contract_internal_function.sol
new file mode 100644
index 000000000..f7dc89048
--- /dev/null
+++ b/test/libsolidity/semanticTests/functionTypes/ternary_contract_internal_function.sol
@@ -0,0 +1,10 @@
+contract C {
+    function f() internal pure returns(uint256) { return 1;}
+    function g() internal pure returns(uint256) { return 2; }
+    function test(bool b) public returns(uint256) {
+        return (b ? C.f : C.g)();
+    }
+}
+// ----
+// test(bool): true -> 1
+// test(bool): false -> 2
diff --git a/test/libsolidity/semanticTests/functionTypes/ternary_contract_library_internal_function.sol b/test/libsolidity/semanticTests/functionTypes/ternary_contract_library_internal_function.sol
new file mode 100644
index 000000000..a29a678d5
--- /dev/null
+++ b/test/libsolidity/semanticTests/functionTypes/ternary_contract_library_internal_function.sol
@@ -0,0 +1,13 @@
+library L {
+    function f() internal pure returns(uint256){ return 1; }
+}
+
+contract C {
+    function g() internal pure returns(uint256) { return 2; }
+    function test(bool b) public returns(uint256) {
+        return (b ? L.f : C.g)();
+    }
+}
+// ----
+// test(bool): true -> 1
+// test(bool): false -> 2
diff --git a/test/libsolidity/semanticTests/functionTypes/ternary_contract_public_function.sol b/test/libsolidity/semanticTests/functionTypes/ternary_contract_public_function.sol
new file mode 100644
index 000000000..6d52017a5
--- /dev/null
+++ b/test/libsolidity/semanticTests/functionTypes/ternary_contract_public_function.sol
@@ -0,0 +1,10 @@
+contract C {
+    function f() public pure returns(uint256) { return 1; }
+    function g() public pure returns(uint256) { return 2; }
+    function test(bool b) public returns(uint256) {
+        return (b ? C.f : C.g)();
+    }
+}
+// ----
+// test(bool): true -> 1
+// test(bool): false -> 2
diff --git a/test/libsolidity/syntaxTests/errors/error_ternary_operator.sol b/test/libsolidity/syntaxTests/errors/error_ternary_operator.sol
new file mode 100644
index 000000000..c4600a858
--- /dev/null
+++ b/test/libsolidity/syntaxTests/errors/error_ternary_operator.sol
@@ -0,0 +1,11 @@
+error MyCustomError(uint, bool);
+
+contract C {
+    function f() pure public {
+        true ? MyCustomError : MyCustomError;
+    }
+}
+
+// ----
+// TypeError 9717: (93-106): Invalid mobile type in true expression.
+// TypeError 3703: (109-122): Invalid mobile type in false expression.
diff --git a/test/libsolidity/syntaxTests/errors/error_ternary_operator_different_types.sol b/test/libsolidity/syntaxTests/errors/error_ternary_operator_different_types.sol
deleted file mode 100644
index 680ab8058..000000000
--- a/test/libsolidity/syntaxTests/errors/error_ternary_operator_different_types.sol
+++ /dev/null
@@ -1,18 +0,0 @@
-error MyCustomError(uint, bool);
-error MyCustomError2(uint, bool);
-error MyCustomError3(uint, bool, bool);
-
-contract C {
-    function f() pure public {
-        true ? MyCustomError : MyCustomError;
-        true ? MyCustomError : MyCustomError2;
-        true ? MyCustomError : MyCustomError3;
-        true ? MyCustomError : true;
-        true ? true : MyCustomError;
-    }
-}
-
-// ----
-// TypeError 1080: (253-290): True expression's type error MyCustomError(uint256,bool) does not match false expression's type error MyCustomError3(uint256,bool,bool).
-// TypeError 1080: (300-327): True expression's type error MyCustomError(uint256,bool) does not match false expression's type bool.
-// TypeError 1080: (337-364): True expression's type bool does not match false expression's type error MyCustomError(uint256,bool).
diff --git a/test/libsolidity/syntaxTests/events/event_ternary_operator.sol b/test/libsolidity/syntaxTests/events/event_ternary_operator.sol
new file mode 100644
index 000000000..0ba773241
--- /dev/null
+++ b/test/libsolidity/syntaxTests/events/event_ternary_operator.sol
@@ -0,0 +1,10 @@
+contract C {
+    event MyCustomEvent(uint);
+    function f() pure public {
+        true ? MyCustomEvent : MyCustomEvent;
+    }
+}
+
+// ----
+// TypeError 9717: (90-103): Invalid mobile type in true expression.
+// TypeError 3703: (106-119): Invalid mobile type in false expression.
diff --git a/test/libsolidity/syntaxTests/events/event_ternary_operator_different_types.sol b/test/libsolidity/syntaxTests/events/event_ternary_operator_different_types.sol
deleted file mode 100644
index ca2f1e1d6..000000000
--- a/test/libsolidity/syntaxTests/events/event_ternary_operator_different_types.sol
+++ /dev/null
@@ -1,17 +0,0 @@
-contract C {
-    event MyCustomEvent(uint);
-    event MyCustomEvent2(uint);
-    event MyCustomEvent3(uint, bool);
-    function f() pure public {
-        true ? MyCustomEvent : MyCustomEvent;
-        true ? MyCustomEvent : MyCustomEvent2;
-        true ? MyCustomEvent : MyCustomEvent3;
-        true ? MyCustomEvent : true;
-        true ? true : MyCustomEvent;
-    }
-}
-
-// ----
-// TypeError 1080: (246-283): True expression's type event MyCustomEvent(uint256) does not match false expression's type event MyCustomEvent3(uint256,bool).
-// TypeError 1080: (293-320): True expression's type event MyCustomEvent(uint256) does not match false expression's type bool.
-// TypeError 1080: (330-357): True expression's type bool does not match false expression's type event MyCustomEvent(uint256).
diff --git a/test/libsolidity/syntaxTests/functionTypes/from_ternary_expression.sol b/test/libsolidity/syntaxTests/functionTypes/from_ternary_expression.sol
new file mode 100644
index 000000000..62ad8aa93
--- /dev/null
+++ b/test/libsolidity/syntaxTests/functionTypes/from_ternary_expression.sol
@@ -0,0 +1,8 @@
+contract C {
+    function f() public pure returns (uint x) {
+        x = (true ? addmod : addmod)(3, 4, 5);
+    }
+}
+// ----
+// TypeError 9717: (81-87): Invalid mobile type in true expression.
+// TypeError 3703: (90-96): Invalid mobile type in false expression.
diff --git a/test/libsolidity/syntaxTests/functionTypes/selector_ternary_contract_external_function.sol b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_contract_external_function.sol
new file mode 100644
index 000000000..847caad06
--- /dev/null
+++ b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_contract_external_function.sol
@@ -0,0 +1,10 @@
+contract C {
+    function f() external pure { }
+    function g() external pure { }
+    function test(bool b) public returns(bytes4) {
+        (b ? C.f : C.g).selector;
+    }
+}
+// ----
+// TypeError 9717: (147-150): Invalid mobile type in true expression.
+// TypeError 3703: (153-156): Invalid mobile type in false expression.
diff --git a/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_contract_public_function.sol b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_contract_public_function.sol
new file mode 100644
index 000000000..5f5edfa9f
--- /dev/null
+++ b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_contract_public_function.sol
@@ -0,0 +1,13 @@
+contract C {
+    function f() public pure { }
+    function g() public pure { }
+}
+
+contract A {
+    function test(bool b) public returns(bytes4) {
+        (b ? C.f : C.g).selector;
+    }
+}
+// ----
+// TypeError 9717: (159-162): Invalid mobile type in true expression.
+// TypeError 3703: (165-168): Invalid mobile type in false expression.
diff --git a/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_contracts_external_function.sol b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_contracts_external_function.sol
new file mode 100644
index 000000000..e015f4315
--- /dev/null
+++ b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_contracts_external_function.sol
@@ -0,0 +1,16 @@
+contract C {
+    function f() external pure { }
+}
+
+contract D {
+    function g() external pure { }
+}
+
+contract A {
+    function test(bool b) public returns(bytes4) {
+        (b ? C.f : D.g).selector;
+    }
+}
+// ----
+// TypeError 9717: (179-182): Invalid mobile type in true expression.
+// TypeError 3703: (185-188): Invalid mobile type in false expression.
diff --git a/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_interface_external_function.sol b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_interface_external_function.sol
new file mode 100644
index 000000000..4109a14ce
--- /dev/null
+++ b/test/libsolidity/syntaxTests/functionTypes/selector_ternary_different_interface_external_function.sol
@@ -0,0 +1,16 @@
+interface I1 {
+    function f() external pure;
+}
+
+interface I2 {
+    function g() external pure;
+}
+
+contract C {
+    function test(bool b) public returns(bytes4) {
+        (b ? I1.f : I2.g).selector;
+    }
+}
+// ----
+// TypeError 9717: (177-181): Invalid mobile type in true expression.
+// TypeError 3703: (184-188): Invalid mobile type in false expression.