| YS0001 | Variable has conflicting implicit type declarations. A variable is being used as different types in different places. |
| YS0002 | Type mismatch. An expression’s type doesn’t match what’s expected (e.g. assigning a number to a boolean). |
| YS0004 | Missing node delimiter. A node is missing its === closing delimiter. |
| YS0005 | Syntax error. Something in the script can’t be parsed. |
| YS0006 | Unclosed command. A << was opened but never closed with >>. |
| YS0007 | Unclosed scope. A control flow block (like <<if>>) isn’t properly closed (missing <<endif>>). |
| YS0011 | Duplicate node title. Two or more nodes have the same title without when: clauses to distinguish them. |
| YS0012 | Jump to undefined node. A <<jump>> or <<detour>> targets a node that doesn’t exist. |
| YS0013 | Invalid function call. A function is called with the wrong number or type of parameters, or doesn’t exist. |
| YS0014 | Invalid or unknown command. A command isn’t recognised. Check spelling or make sure it’s defined in your definitions file. |
| YS0017 | Line has both #line and #shadow tags. A line can’t be both — shadow lines don’t get their own line ID. |
| YS0018 | Duplicate line ID. Every #line: tag in a project must be unique. |
| YS0021 | Stray >> without a matching <<. |
| YS0022 | Command keyword outside of << and >>. Did you forget the angle brackets? |
| YS0025 | Unknown enum member. The value isn’t a known member of the expected enum type. |
| YS0023 | Wrong enum type. The value is from a different enum than what the parameter expects. |
| YS0024 | Enum type expected. The parameter expects an enum value but got something else. |
| YS0026 | Enum format error. Enum values should be written as EnumName.Value. |
| YS0027 | Invalid node name. Node titles can only contain letters, numbers, and underscores. |
| YS0028 | Can’t infer variable type. Declare the variable explicitly with <<declare>>. |
| YS0029 | Can’t determine expression type. The compiler can’t figure out what type this expression evaluates to. |
| YS0030 | Can’t modify a smart variable. Smart variables are computed values and are read-only. |
| YS0031 | Missing when: clause in node group. If some nodes in a group have when: clauses, all must have them (use when: always as a fallback). |
| YS0032 | Duplicate subtitle in node group. Subtitles within a node group must be unique. |
| YS0034 | Incompatible function. A library function has a signature that can’t be used in Yarn scripts. |
| YS0035 | Enum declaration error. |
| YS0036 | Feature requires newer project version. A language feature was used that needs a higher projectFileVersion. |
| YS0037 | Invalid literal value. A constant value couldn’t be parsed. |
| YS0038 | Unresolved type member. A type member access (like Enum.Value) couldn’t be resolved. |
| YS0039 | Variable redeclaration. A variable can only be declared once. |
| YS0040 | Type redeclaration. A type with this name already exists. |
| YS0041 | Internal compiler error. Something unexpected happened. Please file an issue. |
| YS0042 | Unknown line ID for shadow line. The #shadow: tag references a line ID that doesn’t exist. |
| YS0043 | Shadow lines can’t have expressions. Shadow lines must be plain text. |
| YS0044 | Shadow line text mismatch. A shadow line must have the same text as its source line. |
| YS0045 | Smart variable reference loop. A smart variable’s expression references itself through other smart variables. |
| YS0046 | Null default value. Variable declarations must have a non-null default value. |
| YS0047 | Expression took too long to resolve. Try simplifying this expression. |
