Diagnostics · Flowscope Script

Stable compiler diagnostic codes of Flowscope Script, each with a failing and a corrected example.

Every message the compiler reports carries a stable code. The letter names the stage that found the problem; the number never changes meaning, so you can search for it, link to it and silence nothing by accident. Errors stop the script from running; warnings point at code that runs but probably does not do what you meant.

Parse (P…)

Problems found while reading the source text: characters, literals, line structure and syntax forms that Flowscope Script does not have.

Code	Severity	Summary
P001	error	unrecognized token
P002	error	unterminated string literal
P003	error	semicolon is not supported
P004	error	word spelling of a logical operator
P005	error	`??` mixed with `&&` or `\|\|` needs parentheses
P006	error	`while` is not supported
P007	error	template strings are not supported
P008	error	`?.` is not supported
P009	error	postfix `!` is not supported
P011	error	top-level statement is not a declaration
P014	error	`break` and `continue` are not statements
P016	error	expected token
P021	error	invalid color literal
P022	error	unknown string escape
P023	error	match arm in statement form needs a block
P024	error	match expression arm takes an expression, not a block
P025	error	keyword used as a name
P026	error	ternary broken before `?` or `:`
P027	error	second statement on the same line

Setup and declarations (S…)

Declarations that cannot be evaluated before the first bar, misuse of setup-only constructors, subscription arguments and alert declarations.

Code	Severity	Summary
S001	error	live value used in setup
S002	error	built-in cannot run in setup
S005	error	collection capacity must be known before the script runs
S006	error	duplicate panel name
S007	error	constructor does not fit the declaration keyword
S008	error	user function called in setup
S011	error	setup value reads a later declaration
S012	error	empty exchange list in subscription
S013	error	color scale needs matching lists with at least two entries
S015	error	minimum trade size must be positive and finite
S018	error	lambda or collection transform in setup
S019	error	alert constructor outside an alert declaration
S020	error	invalid alert payload type
S022	error	trigger argument does not match the alert payload
S026	error	subscription history cannot be negative
S027	error	the chart subscription cannot be live only

Types and names (T…)

Name resolution and type checking. T0xx names and declarations, T1xx types and literals, T2xx calls, arguments and returns, T3xx user types and match, T4xx handlers, series, plots and lambdas.

Code	Severity	Summary
T001	error	unknown identifier
T002	error	duplicate top-level name
T005	error	unknown type name
T006	error	local hides a built-in namespace
T007	error	name is already bound in this scope
T010	error	script header missing or misplaced
T011	warning	duplicate display title
T013	warning	unused binding
T014	warning	unused subscription
T016	error	duplicate input key
T101	error	type mismatch
T102	error	operator not defined for these operand types
T103	error	float needs an explicit conversion to int
T106	error	invalid map key type
T109	error	type is not indexable
T111	error	invalid timeframe literal
T112	error	zero-length timeframe
T113	error	integer literal out of range
T114	error	invalid session literal
T201	error	unknown named argument
T202	error	positional argument after a named one
T203	error	argument supplied more than once
T204	error	missing argument
T205	error	too many positional values
T206	error	parameter default is not a literal
T207	error	required parameter after an optional one
T208	error	null default for a non-nullable parameter
T211	error	wrong number of return values
T212	error	not every path returns a value
T214	error	destructuring does not match the returned values
T215	error	no overload matches these arguments
T216	error	value cannot be reassigned
T217	error	invalid assignment target
T301	error	type field has no type annotation
T302	error	type contains itself
T303	error	type name is not UpperCamelCase
T304	error	match does not cover every case
T305	warning	null arm on a value that cannot be null
T306	error	record literal has wrong fields
T307	error	duplicate field in a type
T401	error	function calls itself
T402	error	stateful calculation inside a loop
T403	error	indicator inputs come from different timeframes
T405	error	event not available for this subscription
T406	error	duplicate handler
T407	error	handler on a snapshot source
T408	error	indicator on a calendar timeframe
T413	error	indicator length must be known before the script runs
T414	error	indicator length out of range
T415	error	plot method does not match the panel
T416	error	invalid str.format template
T420	error	trade fields are read-only
T422	error	book or profile view kept beyond the current call
T425	error	fill has both a solid color and a gradient
T426	error	lambda in an invalid position or with a block body
T427	error	invalid lambda parameter list
T428	error	stateful call, randomness or drawing inside a lambda
T430	error	collection transform must be its own statement
T442	error	record literal without a type name
T449	warning	isLast read in a close handler

Null safety (N…)

Places where a value that may be missing is used as if it were always present.

Code	Severity	Summary
N001	error	value may be null here
N002	error	null check on a field does not narrow it
N003	error	null needs an explicit type

Collections (C…)

Arrays, rolling buffers and maps: read-only setup data, element types, capacities and subscription series.

Code	Severity	Summary
C001	error	setup collection is read-only
C003	error	collection cannot contain another collection
C004	error	key is missing from a setup map
C005	error	empty array needs a capacity
C006	error	subscription series is read-only

Limits (L…)

Fixed resource limits per script: stateful calls, subscriptions, capacities, inputs, plots and alerts.

Code	Severity	Summary
L001	error	too many stateful call sites
L006	error	too many subscriptions
L007	error	capacity exceeds the supported limit
L008	error	negative capacity
L010	error	too many inputs
L011	error	too many plots
L013	error	too many alerts
L015	error	expressions or blocks nest too deeply

Backtesting and strategies (B…)

The strategy declaration, order functions and broker emulator settings used by the Strategy Tester.

Code	Severity	Summary
B001	error	strategy order outside a handler
B002	error	strategy function without a strategy declaration
B003	error	more than one strategy declaration
B004	error	strategy property set twice
B005	warning	exit refers to an unknown entry id
B006	error	pyramiding is negative
B007	error	quantity is not positive
B008	error	commission or slippage is negative
B009	error	exit target given in ticks and as a price
B010	error	trailOffset without trailPoints
B011	error	leverage out of range
B012	warning	processOrdersOnClose combined with the bar magnifier
B013	error	strategy position read in setup
B014	error	initial capital is not positive

Internal (I…)

Failures of the compiler itself rather than of the script.

Code	Severity	Summary
I000	error	internal compiler error