COMP: Ambiguous type conversion when using Clang 15.0

Problem

As illustrated in Test-one.zip and for Clang 15.0.7, the operations of division, minimum and maximum between a geometricOneField and volScalarField throw an ambiguous-conversion error, e.g.:

develop/src/OpenFOAM/lnInclude/oneI.H:131:12: error: conversion from 'tmp<GeometricField<double, Foam::fvPatchField, Foam::volMesh>>' to 'Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>' is ambiguous

This typically means that the Clang compiler has found more than one possible way to perform the conversion between tmp<GeometricField<...>> to GeometricField<...>, but it cannot decide which one is the correct or intended conversion path without more explicit instructions.

Note that Gcc 7.5.0 does not throw this error.

Solution

In oneI.H, wrapping the return type with Type should resolve the issue - as indicated by @mark.

Environment

api      = 2401
patch    = 240220
HEAD     = d578d48a4f
version  = v2312
compiler = Clang (system) = clang version 15.0.7
mpi      = SYSTEMOPENMPI = mpirun (Open MPI) 1.10.7.0.5e373bf1fd
OS       = Description: openSUSE Leap 15.5
opts     = linux64ClangDPInt32Opt