Fix #1661 - Do not use :edit when jumping inside of a file

autoload/ale/util.vim

@@ -56,7 +56,10 @@ function! ale#util#Open(filename, line, column, options) abort
     if get(a:options, 'open_in_tab', 0)
         call ale#util#Execute('tabedit ' . fnameescape(a:filename))
     else
-        call ale#util#Execute('edit ' . fnameescape(a:filename))
+        " Open another file only if we need to.
+        if bufnr(a:filename) isnot bufnr('')
+            call ale#util#Execute('edit ' . fnameescape(a:filename))
+        endif
     endif
 
     call cursor(a:line, a:column)

test/test_go_to_definition.vader

@@ -187,6 +187,28 @@ Execute(Other files should be jumped to for LSP definition responses):
   AssertEqual [3, 7], getpos('.')[1:2]
   AssertEqual {}, ale#definition#GetMap()
 
+Execute(Locations inside the same file should be jumped to without using :edit):
+  call ale#definition#SetMap({3: {'open_in_tab': 0}})
+  call ale#definition#HandleLSPResponse(
+  \ 1,
+  \ {
+  \   'id': 3,
+  \   'result': {
+  \     'uri': ale#path#ToURI(ale#path#Simplify(expand('%:p'))),
+  \     'range': {
+  \       'start': {'line': 2, 'character': 7},
+  \     },
+  \   },
+  \ }
+  \)
+
+  AssertEqual
+  \ [
+  \ ],
+  \ g:expr_list
+  AssertEqual [3, 7], getpos('.')[1:2]
+  AssertEqual {}, ale#definition#GetMap()
+
 Execute(Other files should be jumped to in tabs for LSP definition responses):
   call ale#definition#SetMap({3: {'open_in_tab': 1}})
   call ale#definition#HandleLSPResponse(