patch 8.2.3175: Vim9: using illegal pointer with nested lambdas.

Problem:    Vim9: using illegal pointer with inline function inside a lambda.
Solution:   Clear eval_tofree_cmdline when advancing to the next line.
            (closes #8578)

src/eval.c

@@ -2177,6 +2177,11 @@ eval_next_line(evalarg_T *evalarg)
 	vim_free(evalarg->eval_tofree);
 	evalarg->eval_tofree = line;
     }
+
+    // Advanced to the next line, "arg" no longer points into the previous
+    // line.
+    VIM_CLEAR(evalarg->eval_tofree_cmdline);
+
     return skipwhite(line);
 }
 

src/testdir/test_vim9_func.vim

@@ -2265,6 +2265,22 @@ def Test_nested_inline_lambda()
         })
   END
   CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+
+      def s:func()
+        range(10)
+          ->mapnew((_, _) => ({
+            key: range(10)->mapnew((_, _) => {
+              return ' '
+            }),
+          }))
+      enddef
+
+      defcomp
+  END
+  CheckScriptSuccess(lines)
 enddef
 
 def Shadowed(): list<number>

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3175,
 /**/
     3174,
 /**/