TS8023

When it fires

The same function, binding, module constant or struct name declared twice in one scope. A struct counts whichever of the three spellings each declaration used: a class, an interface and a type alias of one name are one struct, not declarations that merge.

Example

"use typeshade"

function shade(x: f32): f32 {
  return x * 0.5
}

function shade(x: f32): f32 {
  return x * 0.25
}

@fragment
export function main(@location(0) uv: vec2): vec4 {
  return vec4(uv, shade(uv.x), 1.)
}

Compiled at build time against the pinned compiler, this program gets:

How to fix it

The same program, corrected. It compiles with no diagnostic.

"use typeshade"

function shade(x: f32): f32 {
  return x * 0.5
}

function shadeQuarter(x: f32): f32 {
  return x * 0.25
}

@fragment
export function main(@location(0) uv: vec2): vec4 {
  return vec4(uv, shade(uv.x) + shadeQuarter(uv.y), 1.)
}

The rule this enforces

Rule 4.2 Test

A type alias is another name for its target.

See also

• Types
• Error codes

Source

Where the compiler raises this code at commit 26de7be8, one line per file:

• src/compiler/ts/bindings.ts:139
• src/compiler/ts/link.ts:1033
• src/compiler/ts/lower/control.ts:636
• src/compiler/ts/lower/function.ts:236 (4 sites)
• src/compiler/ts/lower/statement.ts:471 (3 sites)
• src/compiler/ts/module-const.ts:278 (2 sites)
• src/compiler/ts/module-vars.ts:218 (2 sites)
• src/compiler/ts/source-file.ts:763
• src/compiler/ts/structs.ts:267 (2 sites)