Error reference

This page is generated from the compiler's catalog (tccl docs errors). The same explanations appear in tccl check, tccl explain <code> and the playground.

Error messages are always in English because they are part of the compiler's behaviour (and, for language version 1, of chain history). The code, explanation and fix are translated.

Compile errors#

A compile error is shown as file:line:column, with the code, a suggested fix and often a “did you mean” hint. A contract that does not compile is never deployed; on the network, a deployment transaction whose source fails to compile is rejected by the wallet before sending, and pays its fee if it is mined anyway.

C001 — Tab character#

Blocks are defined by indentation and TCCL only accepts spaces, so the meaning of a line never depends on editor settings.

Fix: Replace tabs with 4 spaces.

Messages include: tabs are not allowed

C002 — Indentation#

After a line ending with ':' the next lines must be indented more than it; a block ends when the indentation returns to an outer level.

Fix: Indent the body of every block with the same number of spaces (4 is customary); use 'pass' for an empty block.

Messages include: indentation does not match, unexpected indentation, an indented block, empty block

C003 — Unfinished text#

A text literal must start and end with " on the same line. Escapes: \n \t \" \\.

Fix: Close the quote, or escape inner quotes as \".

Messages include: unterminated, unknown escape

C004 — Invalid literal#

Integers are decimal (underscores allowed) and fit in 128 bits; bytes are written 0x followed by an even number of hex digits. There are no decimals: amounts are integers in motes.

Fix: Write amounts as integers, e.g. 5 * TCN or 250_000_000.

Messages include: invalid number literal, integer literal out of range, hex bytes literal, invalid hex literal

C005 — Contract layout#

A deployable file starts with 'contract Name' and declares at least one init, action or view. Modules may follow as 'module name' sections.

Fix: Put 'contract MyContract' on the first line of code.

Messages include: 'contract <Name>', only one contract, a contract needs at least one, only contains modules

C006 — Unknown name#

Every name must be declared before use: a local 'let', a parameter, a const, a state variable or a built-in context value (caller, value, balance, height, self, origin).

Fix: Check the spelling or declare it, e.g. 'let total: int = 0'.

Messages include: unknown name, unknown variable

C007 — Unknown type#

Types are int, bool, text, bytes, address, list[T], map[K, V] (state only) and the records, enums and interfaces you declare.

Fix: Use one of the built-in types or declare the record/enum.

Messages include: unknown type

C008 — Function call#

Calls must name a built-in or a 'fn' helper with the right number and types of arguments.

Fix: Check the name and the parameters in the declaration.

Messages include: unknown function, takes 0 argument, takes 1 argument, takes 2 argument, takes 3 argument, argument(s),

C009 — Type mismatch#

TCCL never converts types implicitly: an operation or assignment needs exactly the declared type. Conditions must be bool.

Fix: Convert explicitly with to_text, to_bytes or to_int, or change the declared type.

Messages include: expected int, found, expected bool, found, expected text, found, expected bytes, found, expected address, found, cannot add, arithmetic needs, cannot compare, ordering comparisons, need bool operands, compound assignment is not defined, expected a

C010 — Missing return#

A function that declares '-> type' must end with 'return', or with an if/else whose every branch returns.

Fix: Add a final 'return <value>'.

Messages include: must return a, must return on every path, does not return a value

C011 — Views only read#

A view is a free query that anyone can run without a transaction, so it cannot change state, send TCN, emit events, read 'value' or call actions.

Fix: Turn it into an 'action', or move the change into an action.

Messages include: a view cannot, changes state, sends TCN or emits events, not available in a view, view cannot call the action

C012 — Name already used#

Each name is declared once per contract and cannot shadow built-in names (caller, value, len, ...).

Fix: Choose a different name.

Messages include: already declared, is reserved, reserved name, duplicate

C013 — Maps and state lists#

Maps exist only as state variables and are used item by item; state lists and maps cannot be copied or assigned as a whole.

Fix: Use m[key], m.has(key), m.remove(key), xs[i], xs.push(v), len(xs).

Messages include: maps can only be used as state, map keys must be, cannot assign a whole, is a map;, is a state list

C014 — Constants#

Constants are computed at compile time from literals, other constants, arithmetic, enum variants and address("..."), and never change.

Fix: Use a state variable for values that change.

Messages include: is a constant, is not a constant, constant values can only, constant expression, constants must be

C015 — Receiving TCN#

Only functions marked 'payable' (actions and init) can receive TCN; a call to another contract can attach TCN with 'with value' only if the interface marks it payable.

Fix: Add 'payable' to the header: action buy() payable:

Messages include: can be payable, not payable in its interface, 'with value', views cannot receive TCN

C016 — Entry points are not helpers#

init, actions and views are called by transactions and queries; code can only call 'fn' helpers (and other contracts through interfaces).

Fix: Move the shared logic into a 'fn' and call it from both places.

Messages include: is an entry point

C017 — Statement#

A line must do something: assign, call a function, control flow. Comparisons cannot be chained (use 'and').

Fix: Assign the result with 'let' or remove the line.

Messages include: does nothing as a statement, outside of a loop, range() can only, chained comparisons

C018 — Records#

A record groups named, typed fields. Build it with every field named, e.g. Order(buyer: caller, amount: 5); read with order.amount.

Fix: List every field once with 'name: value'.

Messages include: record, has no field, needs every field, named fields, contains itself

C019 — Enums and transitions#

An enum lists named situations. Lines like 'Open -> Paid, Cancelled' declare which changes are allowed; any other change fails when stored.

Fix: Use Enum.Variant and list allowed next variants after '->'.

Messages include: variant, '->'

C020 — Roles and permissions#

'only' restricts who may call an action: members of a role (role admin; grant admin to x) or the address in a state variable.

Fix: Declare 'role name' and grant it in init(): grant name to caller.

Messages include: 'only, unknown role, is a role

C021 — Interfaces#

An interface describes actions and views of another contract. Calls use it: Token(addr).transfer(to, 5). Signatures use int, bool, text, bytes, address and lists.

Fix: Declare the function in the interface exactly as the other contract defines it.

Messages include: interface

C022 — Modules#

A module is reusable source code compiled into the contract ('use std.token' or a 'module name' section). It has no address; its state can only be changed by its own functions.

Fix: Call the module's helpers: token.mint(to, amount).

Messages include: module, std.

C023 — Upgrades#

An upgrade keeps the storage: state variables cannot be removed or change type, records keep their fields and enums keep their variants in order.

Fix: Keep old variables (you may stop using them) and add new ones.

Messages include: upgrade, was removed, storage slot

C024 — Limit reached#

The compiler bounds source size, nesting and counts so that every node can compile any contract quickly and safely.

Fix: Split long expressions with 'let' and large contracts into modules or several contracts.

Messages include: too many, too large, too deep, too deeply, too long, nested too

C025 — Address literal#

address("...") takes a valid bech32m address of the network being compiled for (tc1 mainnet, tct1 testnet, tcr1 regtest).

Fix: Copy the address again and check its prefix.

Messages include: address literal, address prefix, invalid address

C026 — Syntax#

The line does not follow the grammar at the marked position.

Fix: Compare with the language reference or an example.

Messages include: expected

Runtime errors#

A runtime error stops the call. Every effect of the transaction is reverted — storage in every contract involved, TCN sent, events and the value attached to the call. The transaction fee is still paid, because the network did the work. Wallets simulate calls first and refuse to send a call that would fail.

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