updated for version 7.4.272

Problem:    Using just "$" does not cause an error message.
Solution:   Check for empty environment variable name. (Christian Brabandt)

src/eval.c

@@ -7798,7 +7798,7 @@ string2float(text, value)
  * Get the value of an environment variable.
  * "arg" is pointing to the '$'.  It is advanced to after the name.
  * If the environment variable was not set, silently assume it is empty.
- * Always return OK.
+ * Return FAIL if the name is invalid.
  */
     static int
 get_env_tv(arg, rettv, evaluate)
@@ -7817,8 +7817,9 @@ get_env_tv(arg, rettv, evaluate)
     len = get_env_len(arg);
     if (evaluate)
     {
-	if (len != 0)
+	if (len == 0)
-	{
+           return FAIL; /* can't be an environment variable */
+
 	cc = name[len];
 	name[len] = NUL;
 	/* first try vim_getenv(), fast for normal environment vars */
@@ -7842,7 +7843,7 @@ get_env_tv(arg, rettv, evaluate)
 	    }
 	}
 	name[len] = cc;
-	}
+
 	rettv->v_type = VAR_STRING;
 	rettv->vval.v_string = string;
     }

src/testdir/test_eval.in

@@ -183,6 +183,13 @@ endfun
 :" script-local function used in Funcref must exist.
 :so test_eval_func.vim
 :"
+:" Using $ instead of '$' must give an error
+:try
+: call append($, 'foobar')
+:catch
+:$put =v:exception
+:endtry
+:"
 :/^start:/+1,$wq! test.out
 :" vim: et ts=4 isk-=\: fmr=???,???
 :call getchar()

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    272,
 /**/
     271,
 /**/