Fix abi.encodeCall checks

Author: timweri

Changelog.md

@@ -13,6 +13,7 @@ Compiler Features:
 
 Bugfixes:
  * Commandline Interface: Disallow the following options outside of the compiler mode: ``--via-ir``,``--metadata-literal``, ``--metadata-hash``, ``--model-checker-show-unproved``, ``--model-checker-div-mod-no-slacks``, ``--model-checker-engine``, ``--model-checker-invariants``, ``--model-checker-solvers``, ``--model-checker-timeout``, ``--model-checker-contracts``, ``--model-checker-targets``.
+ * Type Checker: Fix null dereference in `abi.encodeCall` type checking of free function.
 
 
 ### 0.8.15 (2022-06-15)

libsolidity/analysis/TypeChecker.cpp

@@ -2195,14 +2195,28 @@ void TypeChecker::typeCheckABIEncodeCallFunction(FunctionCall const& _functionCa
 	)
 	{
 		string msg = "Expected regular external function type, or external view on public function.";
-		if (externalFunctionType->kind() == FunctionType::Kind::Internal)
-			msg += " Provided internal function.";
-		else if (externalFunctionType->kind() == FunctionType::Kind::DelegateCall)
-			msg += " Cannot use library functions for abi.encodeCall.";
-		else if (externalFunctionType->kind() == FunctionType::Kind::Creation)
-			msg += " Provided creation function.";
-		else
-			msg += " Cannot use special function.";
+
+		switch (externalFunctionType->kind())
+		{
+			case FunctionType::Kind::Internal:
+				msg += " Provided internal function.";
+				break;
+			case FunctionType::Kind::DelegateCall:
+				msg += " Cannot use library functions for abi.encodeCall.";
+				break;
+			case FunctionType::Kind::Creation:
+				msg += " Provided creation function.";
+				break;
+			case FunctionType::Kind::Event:
+				msg += " Cannot use events for abi.encodeCall.";
+				break;
+			case FunctionType::Kind::Error:
+				msg += " Cannot use errors for abi.encodeCall.";
+				break;
+			default:
+				msg += " Cannot use special function.";
+		}
+
 		SecondarySourceLocation ssl{};
 
 		if (externalFunctionType->hasDeclaration())
@@ -2213,10 +2227,14 @@ void TypeChecker::typeCheckABIEncodeCallFunction(FunctionCall const& _functionCa
 				externalFunctionType->declaration().scope() == m_currentContract
 			)
 				msg += " Did you forget to prefix \"this.\"?";
-			else if (util::contains(
-				m_currentContract->annotation().linearizedBaseContracts,
-				externalFunctionType->declaration().scope()
-			) && externalFunctionType->declaration().scope() != m_currentContract)
+			else if (
+				m_currentContract &&
+				externalFunctionType->declaration().scope() != m_currentContract &&
+				util::contains(
+					m_currentContract->annotation().linearizedBaseContracts,
+					externalFunctionType->declaration().scope()
+				)
+			)
 				msg += " Functions from base contracts have to be external.";
 		}
 

test/libsolidity/syntaxTests/abiEncoder/abi_encodeCall_error_free_function.sol

@@ -0,0 +1,7 @@
+error E(uint);
+
+function f() {
+    abi.encodeCall(E, (1));
+}
+// ----
+// TypeError 3509: (50-51): Expected regular external function type, or external view on public function. Cannot use errors for abi.encodeCall.

test/libsolidity/syntaxTests/abiEncoder/abi_encodeCall_event_free_function.sol

@@ -0,0 +1,9 @@
+library L {
+    event E(uint);
+}
+
+function f() {
+    abi.encodeCall(L.E, (1));
+}
+// ----
+// TypeError 3509: (68-71): Expected regular external function type, or external view on public function. Cannot use events for abi.encodeCall.

test/libsolidity/syntaxTests/abiEncoder/abi_encodeCall_free_func.sol

@@ -0,0 +1,7 @@
+function g(uint) {}
+
+function f() {
+    abi.encodeCall(g, (1));
+}
+// ----
+// TypeError 3509: (55-56): Expected regular external function type, or external view on public function. Provided internal function.

test/libsolidity/syntaxTests/abiEncoder/abi_encodeCall_on_lib_func_in_free_func.sol

@@ -0,0 +1,9 @@
+library L {
+    function g() external {}
+}
+
+function f() {
+    abi.encodeCall(L.g, (1));
+}
+// ----
+// TypeError 3509: (78-81): Expected regular external function type, or external view on public function. Cannot use library functions for abi.encodeCall.