patch 8.2.1154: Vim9: crash when using imported function

Problem:    Vim9: crash when using imported function.
Solution:   Check for a function type.  Set the script context when calling a
            function. (closes #6412)

src/testdir/test_vim9_script.vim

@@ -911,10 +911,10 @@ func Test_import_fails_without_script()
   CheckRunVimInTerminal
 
   " call indirectly to avoid compilation error for missing functions
-  call Run_Test_import_fails_without_script()
+  call Run_Test_import_fails_on_command_line()
 endfunc
 
-def Run_Test_import_fails_without_script()
+def Run_Test_import_fails_on_command_line()
   let export =<< trim END
     vim9script
     export def Foo(): number
@@ -1013,6 +1013,35 @@ def Test_vim9script_funcref()
   delete('Xscript.vim')
 enddef
 
+" Check that when searcing for "FilterFunc" it doesn't find the import in the
+" script where FastFilter() is called from.
+def Test_vim9script_funcref_other_script()
+  let filterLines =<< trim END
+    vim9script
+    export def FilterFunc(idx: number, val: number): bool
+      return idx % 2 == 1
+    enddef
+    export def FastFilter(): list<number>
+      return range(10)->filter('FilterFunc')
+    enddef
+  END
+  writefile(filterLines, 'Xfilter.vim')
+
+  let lines =<< trim END
+    vim9script
+    import {FilterFunc, FastFilter} from './Xfilter.vim'
+    def Test()
+      let x: list<number> = FastFilter()
+    enddef
+    Test()
+  END
+  writefile(lines, 'Ximport.vim')
+  assert_fails('source Ximport.vim', 'E121:')
+
+  delete('Xfilter.vim')
+  delete('Ximport.vim')
+enddef
+
 def Test_vim9script_reload_delfunc()
   let first_lines =<< trim END
     vim9script