patch 9.0.1624: crash when calling object constructor

Problem:    Crash when calling object constructor from legacy script. (Israel
            Chauca Fuentes)
Solution:   Pass a pointer for "ufunc". (closes #12502)

src/structs.h

@@ -2184,7 +2184,9 @@ typedef struct {
     linenr_T	fe_lastline;	// last line of range
     int		*fe_doesrange;	// if not NULL: return: function handled range
     int		fe_evaluate;	// actually evaluate expressions
-    partial_T	*fe_partial;	// for extra arguments
+    ufunc_T	*fe_ufunc;	// function to be called, when NULL lookup by
+				// name
+    partial_T	*fe_partial;	// for "dict" and extra arguments
     dict_T	*fe_selfdict;	// Dictionary for "self"
     object_T	*fe_object;	// object, e.g. for "this.Func()"
     typval_T	*fe_basetv;	// base for base->method()

src/testdir/test_vim9_class.vim

@@ -1767,6 +1767,29 @@ def Test_closure_in_class()
   v9.CheckScriptSuccess(lines)
 enddef
 
+def Test_call_constructor_from_legacy()
+  var lines =<< trim END
+      vim9script
+
+      var newCalled = 'false'
+
+      class A
+        def new()
+          newCalled = 'true'
+        enddef
+      endclass
+
+      export def F(options = {}): any
+        return A
+      enddef
+
+      g:p = F()
+      legacy call p.new()
+      assert_equal('true', newCalled)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
 def Test_defer_with_object()
   var lines =<< trim END
       vim9script

src/userfunc.c

@@ -3665,6 +3665,9 @@ call_func(
 
     if (partial != NULL)
 	fp = partial->pt_func;
+    if (fp == NULL)
+	fp = funcexe->fe_ufunc;
+
     if (fp == NULL)
     {
 	// Make a copy of the name, if it comes from a funcref variable it
@@ -4161,8 +4164,10 @@ trans_function_name_ext(
 
     if (lv.ll_ufunc != NULL)
     {
+	if (ufunc != NULL)
 	    *ufunc = lv.ll_ufunc;
 	name = vim_strsave(lv.ll_ufunc->uf_name);
+	*pp = end;
 	goto theend;
     }
 
@@ -6204,6 +6209,7 @@ ex_call(exarg_T *eap)
     int		len;
     int		failed = FALSE;
     funcdict_T	fudi;
+    ufunc_T	*ufunc = NULL;
     partial_T	*partial = NULL;
     evalarg_T	evalarg;
     type_T	*type = NULL;
@@ -6227,7 +6233,7 @@ ex_call(exarg_T *eap)
     }
 
     tofree = trans_function_name_ext(&arg, NULL, FALSE, TFN_INT,
-			     &fudi, &partial, vim9script ? &type : NULL, NULL);
+			   &fudi, &partial, vim9script ? &type : NULL, &ufunc);
     if (fudi.fd_newkey != NULL)
     {
 	// Still need to give an error message for missing key.
@@ -6275,6 +6281,7 @@ ex_call(exarg_T *eap)
 
 	CLEAR_FIELD(funcexe);
 	funcexe.fe_check_type = type;
+	funcexe.fe_ufunc = ufunc;
 	funcexe.fe_partial = partial;
 	funcexe.fe_selfdict = fudi.fd_dict;
 	funcexe.fe_firstline = eap->line1;

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1624,
 /**/
     1623,
 /**/