Embedded backend does not support "shrinking" domains

[tehrengruber]

Example:

@field_operator function lap(in_field::Field{Tuple{IDim_, JDim_}, Float64})
    return in_field +
           in_field(Ioff[1]) +
           in_field(Ioff[-1]) +
           in_field(Joff[1]) +
           in_field(Joff[-1])
end

Error:

ERROR: LoadError: DimensionMismatch: dimensions must match: a has dims (1:4, 1:4), b has dims (2:5, 1:4), mismatch at 1
Stacktrace:
 [1] promote_shape
   @ ./indices.jl:178 [inlined]
 [2] promote_shape(a::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}}, b::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}})
   @ Base ./indices.jl:169
 [3] +(A::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}}, B::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}})
   @ Base ./arraymath.jl:7
 [4] +
   @ ./operators.jl:587 [inlined]
 [5] lapᐞ0(in_field::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}})
   @ Main ~/CSCS/GridTools.jl/test/laplacian_test.jl:22
 [6] backend_execution(backend::Val{:embedded}, fo::GridTools.FieldOp, args::Tuple{Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}}}, kwargs::@Kwargs{}, out::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}}, is_outermost_fo::Bool)
   @ GridTools ~/CSCS/GridTools.jl/src/GridTools.jl:0
 [7] (::GridTools.FieldOp)(args::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}}; offset_provider::Dict{String, Dimension}, backend::String, out::Field{Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Float64, 2, Tuple{Dimension{:IDim_, HORIZONTAL}, Dimension{:JDim_, HORIZONTAL}}, Matrix{Float64}}, kwargs::@Kwargs{})
   @ GridTools ~/CSCS/GridTools.jl/src/GridTools.jl:524
 [8] top-level scope
   @ ~/CSCS/GridTools.jl/test/laplacian_test.jl:33
in expression starting at /Users/lorenzovarese/CSCS/GridTools.jl/test/laplacian_test.jl:33