> For the complete documentation index, see [llms.txt](https://guide.cronuszen.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guide.cronuszen.com/gpcscripting/gpc-script-guide/troubleshooting/compiler-diagnostic-catalog/semantic-warnings-gpc30xx.md).

# Semantic warnings (GPC30xx)

### GPC3000 — REMAP\_NULL Deprecated

```
REMAP_NULL has been deprecated, use unmap instead.
```

**Severity:** Warning (tagged *deprecated*)

A `remap` statement maps a button to `REMAP_NULL`. The construct still compiles, but the dedicated `unmap` statement replaces it.

***

### GPC3001 — `int` Deprecated in Const Arrays

```
Type 'int' is deprecated in const array declarations. Use 'int16' instead.
```

**Severity:** Warning (tagged *deprecated*)

A const array is declared with the legacy `int` element type. It still compiles as a 16-bit signed array; spell it `int16`.

***

### GPC3002 — `char` Deprecated in Const Arrays

```
Type 'char' is deprecated in const array declarations. Use 'int8' instead.
```

**Severity:** Warning (tagged *deprecated*)

Legacy `char` element type on a const array; use `int8`.

***

### GPC3003 — `byte` Deprecated in Const Arrays

```
Type 'byte' is deprecated in const array declarations. Use 'uint8' instead.
```

**Severity:** Warning (tagged *deprecated*)

Legacy `byte` element type on a const array; use `uint8`.

***

### GPC3004 — Unreachable Code

```
Unreachable code detected
```

**Severity:** Warning (tagged *unnecessary*)

A statement follows a terminating statement (`return`, `break`, or `continue`) in the same block, so it can never execute. The editor renders the dead statements grayed out.

```c
function f() {
    return 1;
    set_val(PS4_R2, 100);   // GPC3004 — never runs
}
```

***

### GPC3005 — Dead Function Removed

```
Function '{name}' is never called and has been removed
```

**Severity:** Warning

A user-defined function is not reachable from `main`, `init`, or any combo, so the dead-code optimizer drops it entirely — it consumes no bytecode or variable slots. Delete it, or call it if the omission was accidental.

***

### GPC3006 — Unused Combo Removed

```
Combo '{name}' is never run and has been removed
Fcombo '{name}' is never run and has been removed
```

**Severity:** Warning

A combo (or fcombo) is never started — there is no reachable `combo_run`, `combo_restart`, or `call` referencing it — so it has been removed from the compiled output.

***

### GPC3007 — Dead Control Flow

```
Condition is always false
Condition is always false; loop body will never execute
```

**Severity:** Warning (tagged *unnecessary*)

An `if`/`else if` condition, or a `while`/`for` condition, folds to a constant false at compile time. The guarded body can never run and is eliminated.

***

### GPC3008 — Combo Runs Itself

```
Combo '{name}' is trying to {combo_run|combo_resume}() itself. This has no effect since the combo is already running.
```

**Severity:** Warning

Inside a combo body, `combo_run` or `combo_resume` is invoked with that same combo's name. The combo is by definition already running at that point, so the call is a no-op (contrast with `call`, which is an error — see GPC4015).

***

### GPC3009 — Parameter Shadows Global

```
Function parameter '{name}' shadows {kind} '{name}' declared on {location}.
```

Or without the location for built-in constants.

**Severity:** Warning

A function parameter has the same name as a global variable, constant, define, enum member, const array, or built-in constant. Inside the function the parameter wins, which frequently surprises: writes go to the parameter, not the global. Rename the parameter.

***

### GPC3010 — Built-in Pattern Match

```
Function '{name}' matches built-in '{name}' ({pattern} pattern) and will be dropped
```

**Severity:** Warning (tagged *unnecessary*)

A user-defined function named after a pattern-detectable built-in (`min`, `max`, `clamp`, ...) implements exactly the same logic as the built-in. The compiler drops the user function and routes calls to the built-in, saving bytecode. If your implementation intentionally differs, it raises GPC4025 instead.

***

### GPC3011 — Always-True Condition

```
Condition is always true
```

**Severity:** Warning (tagged *unnecessary*)

An `if`/`else if` condition folds to constant true; the check is removed and the branch always taken. Any `else` branch becomes dead code.

***

### GPC3012 — Const Array Fits int8

```
Const array '{name}' uses {type} but all values fit in int8. Consider using int8 instead.
```

**Severity:** Warning

A const array declared as `int16`, `int`, `uint16`, `int24`, `uint24`, or `int32` has every value within `int8` range (`-128..127`). Narrowing the declared type saves data-section space; `int8`/`uint8`/`char`/`byte`/`image`/`string`/`ps5adt` arrays are never checked (already narrowest, or not numerically narrowable). When the values fit both `int8` and `uint8`, the suggestion matches the declared type's signedness.

***

### GPC3013 — Const Array Fits uint8

```
Const array '{name}' uses {type} but all values fit in uint8. Consider using uint8 instead.
```

**Severity:** Warning

Same population as GPC3012, reported when the values fit `uint8` range (`0..255`) instead.

***

### GPC3014 — Const Array Fits int16

```
Const array '{name}' uses {type} but all values fit in int16. Consider using int16 instead.
```

**Severity:** Warning

Only checked for const arrays declared as `int24`, `uint24`, or `int32` whose values all fit `int16` range.

***

### GPC3015 — Const Array Fits uint16

```
Const array '{name}' uses {type} but all values fit in uint16. Consider using uint16 instead.
```

**Severity:** Warning

Same population as GPC3014, reported when the values fit `uint16` range instead.

***

### GPC3016 — Const Array Fits int24

```
Const array '{name}' uses {type} but all values fit in int24. Consider using int24 instead.
```

**Severity:** Warning

Only checked for const arrays declared as `int32` whose values all fit `int24` range, and only on devices that support the `int24` element type.

***

### GPC3017 — Const Array Fits uint24

```
Const array '{name}' uses {type} but all values fit in uint24. Consider using uint24 instead.
```

**Severity:** Warning

Same population as GPC3016, reported when the values fit `uint24` range instead.

***

### GPC3018 — Reference to Removed Combo

```
'{keyword}({combo})' has been removed because combo '{combo}' was removed
'{keyword}({combo})' is always 0 because combo '{combo}' was removed
```

**Severity:** Warning

Follow-up to GPC3006: surviving code still references a combo that was removed — e.g. `combo_running(X)` where combo `X` is never actually started anywhere. Expression keywords (`combo_running(X)`, `combo_suspended(X)`, ...) are folded to the constant `0`; statement keywords that merely control an already-running combo (`combo_stop(X);`, `combo_suspend(X);`, `combo_resume(X);`) are dropped along with the combo. `combo_run(X)` and `combo_restart(X)` can never trigger this warning — they count as starting the combo, so a combo they reference is not removed in the first place.

***

### GPC3019 — Ambiguous Number

```
You should put spaces between - and the number in '-{value}'.
```

**Severity:** Warning

A `-` sits glued to a number where a binary subtraction was expected, with a space before the `-` but none after it (e.g. `5 -1`) — a spelling that reads ambiguously between "five minus one" and "five, negative one". This fires only for that specific spacing; a fully-spaced `5 - 1` and a fully-glued `x-1` are both left alone as unambiguous.

If you ignore the warning, the compiler treats it as **subtraction**: `x = 5 -1` compiles to `x = 4` — it is *not* read as the number negative-one. The warning exists because a reader (or you, later) may have intended a negative literal, especially in an argument list. Nothing is wrong if subtraction was what you meant — add a space on both sides (`5 - 1`) to make the intent explicit and silence the warning. If a negative literal was intended, separate it properly (e.g. put the comma before `-1`).

```c
int x;
main {
    x = 5 -1;   // GPC3019 — parses as subtraction: x = 4
}
```


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