New gfortran bug test case

Author: nncarlson

gfortran-bugs/CMakeLists.txt

@@ -5,6 +5,8 @@ include(testing)
 
 project(gfortran-bug Fortran)
 
+add_compiler_test(SOURCES gfortran-20200402-file1.f90 gfortran-20200402-file2.f90
+    LINK_ONLY LABELS PR94463)
 add_compiler_test(SOURCES gfortran-20190202.f90 RUN_ONLY LABELS PR89174)
 add_compiler_test(SOURCES gfortran-20180610.f90 LABELS PR86100
     COMPILE_FLAGS "-g -fcheck=bounds")

gfortran-bugs/gfortran-20200402-file1.f90

@@ -0,0 +1,6 @@
+! See gfortran-20200402-file2.f90 for description
+
+module scalar_func_class
+  type, abstract :: scalar_func
+  end type
+end module

gfortran-bugs/gfortran-20200402-file2.f90

@@ -0,0 +1,39 @@
+!! https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94463
+!!
+!! LINK FAILURE
+!!
+!! In this example the compiler generates a reference to the undefined
+!! symbol __vtab_scalar_func_class_Scalar_func.3804. The example is split
+!! across two source files (see gfortran-20200402-file1.f90). Note that
+!! the symbol __scalar_func_class_MOD___vtab_scalar_func_class_Scalar_func
+!! is defined in gfortran-20200402-file1.o.
+!!
+!! This failure appears to occur for all versions of gfortran.
+!!
+!! $ gfortran gfortran-20200402-file1.f90 -c
+!! $ gfortran gfortran-20200402-file2.f90 gfortran-20200402-file1.o
+!! /usr/bin/ld: /tmp/ccNS7CfH.o: in function `__fubar_MOD_edit_short':
+!! gfortran-20200402-file2.f90:(.text+0x1f): undefined reference to `__vtab_scalar_func_class_Scalar_func.3905'
+!! /usr/bin/ld: gfortran-20200402-file2.f90:(.text+0x8f): undefined reference to `__vtab_scalar_func_class_Scalar_func.3905'
+!! collect2: error: ld returned 1 exit status
+!!
+
+module material_model_type
+contains
+  subroutine alloc_phase_prop(func)
+    use scalar_func_class, only: scalar_func
+    class(scalar_func), allocatable, intent(out) :: func
+  end subroutine
+end module
+
+module fubar
+contains
+  subroutine edit_short
+    use material_model_type, only: alloc_phase_prop
+    use scalar_func_class, only: scalar_func
+    class(scalar_func), allocatable :: f
+    call alloc_phase_prop(f)
+  end subroutine
+end module
+
+end