Add more error messages

source/compiler/compiler.go

@@ -790,7 +790,7 @@ NodeTypeSwitch:
 				cp.put(vm.Notb, cp.That())
 				cp.Emit(vm.Jmp, cp.CodeTop()+2)
 				cp.vmComeFrom(boolTest)
-				cp.Emit(vm.Asgm, cp.That(), cp.reserveError("vm/bool/not", node.GetToken()))
+				cp.Emit(vm.Asgm, cp.That(), cp.reserveError("vm/bool/not", node.GetToken()), cp.That())
 				rtnTypes, rtnConst = AltType(values.ERROR, values.BOOL), cst
 				break NodeTypeSwitch
 			default:
@@ -881,7 +881,7 @@ NodeTypeSwitch:
 					cp.Emit(vm.Rpop)
 				}
 			case v.types.Contains(values.FUNC):
-				errorLoc := cp.reserveError("vm/apply/func", node.GetToken())
+				errorLoc := cp.reserveError("vm/apply/func", node.GetToken(), v.MLoc)
 				cp.Cm("Prefix variable might be lambda. Emitting type check.", node.GetToken())
 				funcTest := cp.vmIf(vm.Qtyp, v.MLoc, uint32(values.FUNC))
 				cp.put(vm.Dofn, operands...)

source/err/errorfile.go

@@ -2566,6 +2566,25 @@ var ErrorCreatorMap = map[string]ErrorCreator{
 		},
 	},
 
+	"vm/apply/func": {
+		Message: func(tok *token.Token, args ...any) string {
+			return "value is not of type 'func'"
+		},
+		Explanation: func(errors Errors, pos int, tok *token.Token, args ...any) string {
+			return "It only makes sense to apply a value to an expression if the value " +
+			       "is a lambda function."
+		},
+	},
+
+	"vm/bool/not": {
+		Message: func(tok *token.Token, args ...any) string {
+			return "value is not of type 'bool'"
+		},
+		Explanation: func(errors Errors, pos int, tok *token.Token, args ...any) string {
+			return "The built-in 'not' operator can only be applied to values of boolean types."
+		},
+	},
+
 	"vm/div/float": {
 		Message: func(tok *token.Token, args ...any) string {
 			return "division by zero"