errors and warnings / names / E1004

E1004 error

A parameter's default reads that parameter or a later one, which is not set yet (in Lua every parameter is in scope there, so the name is the parameter, not an outer one)

area: names (x1xxx)
fails the build: yes
in plain Lua files: reported as W1004

A parameter's default value reads that parameter or a later one. Every parameter is in scope in a default, as in the Lua it compiles to, so the name means the parameter itself, which isn't set yet: it is nil there, even when an outer local has the same name. A default may read earlier parameters only. Reorder the parameters, or rename the parameter to read an outer local of that name.

Example

× failswowlua

local function resize(width: number = height, height: number = 100)    print(width, height)endresize()

✓ compileswowlua

local function resize(height: number = 100, width: number = height)    print(width, height)endresize()

The compiler reports it like this:

error[E1004]: `height` here is the parameter, which is not set yet (a default reads only earlier parameters); to read an outer `height`, give the parameter another name
  ┌─ src/main.wowlua:1:39
  │
1 │ local function resize(width: number = height, height: number = 100)
  │                                       ^^^^^^ here

code	message
W1004	Local shadows another local, or a `local function` is named like a local of the same block; also a parameter named `self` inside a class's method or constructor, which hides the instance (a plain `function M:m()`'s `self` may be shadowed, as frame handlers do)

Offline

terminal

$ wowlua explain E1004
E1004 (error): A parameter's default reads that parameter or a later one, which is not set yet (in Lua every parameter is in scope there, so the name is the parameter, not an outer one)

source on GitHub ↗

Example

Related codes

Offline