Fix equality for FieldVectors with different type

Before this commit, == for FieldVectors with different types was falling
back to the AbstractArray ==, resulting in false positives. Now
FieldVectors with different types are always considered different.

NEWS.md

@@ -7,6 +7,14 @@ main
 - Extended `create_dss_buffer` and `weighted_dss!` for `FieldVector`s, rather than
 just `Field`s. PR [#2000](https://github.com/CliMA/ClimaCore.jl/pull/2000).
 
+### ![][badge-🐛bugfix] Fix equality for `FieldVector`s with different type
+
+Due to a bug, `==` was not recursively checking `FieldVector`s with different
+types, which resulted in false positives. This is now fixed and `FieldVector`s
+are always considered different.
+
+PR [#2021](https://github.com/CliMA/ClimaCore.jl/pull/2021).
+
 v0.14.16
 -------
 

src/Fields/fieldvector.jl

@@ -494,3 +494,8 @@ rcompare(x::T, y::T) where {T <: Union{FieldVector, NamedTuple}} =
 # Define == to call rcompare for two fieldvectors of the same
 # exact type.
 Base.:(==)(x::T, y::T) where {T <: FieldVector} = rcompare(x, y)
+
+# FieldVectors with different types are always different. We need this
+# explicitly because FieldVectors are AbstractArrays, so we have to override
+# the default method
+Base.:(==)(x::T1, y::T2) where {T1 <: FieldVector, T2 <: FieldVector} = false