diff --git a/libsolidity/ast/AST.cpp b/libsolidity/ast/AST.cpp
index 80f5d642454c..16c9b2d2c1bc 100644
--- a/libsolidity/ast/AST.cpp
+++ b/libsolidity/ast/AST.cpp
@@ -312,7 +312,7 @@ FunctionTypePointer FunctionDefinition::functionType(bool _internal) const
 		case Declaration::Visibility::External:
 			return {};
 		default:
-			solAssert(false, "visibility() should not return a Visibility");
+			solAssert(false, "visibility() should return a Visibility");
 		}
 	}
 	else
@@ -328,7 +328,7 @@ FunctionTypePointer FunctionDefinition::functionType(bool _internal) const
 		case Declaration::Visibility::External:
 			return make_shared<FunctionType>(*this, _internal);
 		default:
-			solAssert(false, "visibility() should not return a Visibility");
+			solAssert(false, "visibility() should return a Visibility");
 		}
 	}