The WGSL spec has a note stating "The number of available locations for an entry point is defined by the WebGPU API." But there's not a clear-cut definition of that in the WebGPU spec anywhere.

It would be helpful to have a note in the WebGPU spec that points out what the limiting factors on locations are which the WGSL spec can then in turn link to.

From the matrix chat:

kainino: it's kind of alluding to just location numbers so maxVertexAttributes, maxInterStageShaderVariables, and maxColorAttachments
but there's also that section [Brandon] linked to, maxColorAttachmentBytesPerSample, maxInterStageShaderComponents, maybe others that are in the same space of things