Fix crash when declaring function selector of parent class as public constant

libsolidity/analysis/FunctionCallGraph.cpp

@@ -178,6 +178,23 @@ bool FunctionCallGraphBuilder::visit(MemberAccess const& _memberAccess)
 			m_graph.bytecodeDependency.emplace(&accessedContractType.contractDefinition(), &_memberAccess);
 		}
 
+	// Handle .selector property access (not function calls named "selector") - the result type is bytes4, not FunctionType
+	if (memberName == "selector" && !dynamic_cast<FunctionType const*>(_memberAccess.annotation().type))
+		// Check if we're accessing .selector on a function type
+		if (auto const* exprFunctionType = dynamic_cast<FunctionType const*>(exprType))
+			// Only track internal functions (they need internal function IDs)
+			if (exprFunctionType->kind() == FunctionType::Kind::Internal)
+			{
+				// Ensure we have a concrete function definition
+				if (auto const* functionDef = dynamic_cast<FunctionDefinition const*>(&exprFunctionType->declaration()))
+				{
+					// Add function to call graph so it gets assigned an internal function ID
+					functionReferenced(*functionDef, false);
+					return true;
+				}
+			}
+
+
 	auto functionType = dynamic_cast<FunctionType const*>(_memberAccess.annotation().type);
 	auto functionDef = dynamic_cast<FunctionDefinition const*>(_memberAccess.annotation().referencedDeclaration);
 	if (!functionType || !functionDef || functionType->kind() != FunctionType::Kind::Internal)

test/libsolidity/semanticTests/functionSelector/function_selector_as_constant.sol

@@ -0,0 +1,98 @@
+// File-level constant
+bytes4 constant FILE_LEVEL_SELECTOR = Base.testFunc.selector;
+
+contract Base {
+    function testFunc() public {}
+}
+
+library TestLib {
+    function libFunc() public {}
+    bytes4 public constant LIB_SELECTOR = TestLib.libFunc.selector;
+}
+
+contract B {
+    function g() public {}
+}
+
+contract ModifierTest {
+    function modFunc() public {}
+
+    modifier testModifier(bytes4 selector) {
+        require(selector == this.modFunc.selector);
+        _;
+    }
+
+    constructor() testModifier(this.modFunc.selector) {
+    }
+}
+
+// Testing constructor args when called after 'is' 
+contract InheritanceTest is B {
+    bytes4 public constant INHERIT_SELECTOR = B.g.selector;
+
+    constructor(bytes4 expectedSelector) {
+        assert(INHERIT_SELECTOR == expectedSelector);
+    }
+}
+
+// Unrelated contract with constants
+contract UnrelatedContract {
+    bytes4 public constant UNRELATED_SELECTOR = B.g.selector;
+}
+
+// Main test contract - should be last
+contract C is B {
+    bytes4 public constant SELECTOR = B.g.selector;
+
+    // State variable initialization
+    bytes4 public stateSelector = B.g.selector;
+
+    // Immutable initialization
+    bytes4 public immutable IMMUTABLE_SELECTOR = B.g.selector;
+
+    constructor() {
+        assert(SELECTOR == B.g.selector);
+        assert(stateSelector == B.g.selector);
+        assert(IMMUTABLE_SELECTOR == B.g.selector);
+    }
+
+    function testFunctionReference() public view returns (bytes4) {
+        // Using function reference without calling it - just accessing selector
+        return B.g.selector;
+    }
+
+    function testFileLevelConstant() public pure returns (bytes4) {
+        return FILE_LEVEL_SELECTOR;
+    }
+
+    function testLibraryConstant() public pure returns (bytes4) {
+        return TestLib.LIB_SELECTOR;
+    }
+
+    function testUnrelatedConstant() public pure returns (bytes4) {
+        // Test that we can access selector from unrelated contract's function
+        return B.g.selector;
+    }
+
+    function testConstantNegation() public pure returns (bytes4) {
+        // Force ConstantEvaluator to run by using negation on the constant
+        return ~SELECTOR;
+    }
+
+    function testConstantArithmetic() public pure returns (bytes4) {
+        // Force ConstantEvaluator to run by using arithmetic on the constant
+        return bytes4(uint32(SELECTOR) + 1);
+    }
+}
+
+
+// ----
+// SELECTOR() -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
+// stateSelector() -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
+// IMMUTABLE_SELECTOR() -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
+// testFunctionReference() -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
+// testFileLevelConstant() -> 0x037a417c00000000000000000000000000000000000000000000000000000000
+// testLibraryConstant() -> 0xb1678ce400000000000000000000000000000000000000000000000000000000
+// testUnrelatedConstant() -> 0xe2179b8e00000000000000000000000000000000000000000000000000000000
+// testConstantNegation() -> 0x1de8647100000000000000000000000000000000000000000000000000000000
+// testConstantArithmetic() -> 0xe2179b8f00000000000000000000000000000000000000000000000000000000