patch 8.2.2575: Vim9: a function name with "->" in the next line doesn't work

Problem:    Vim9: a function name with "->" in the next line doesn't work.
Solution:   Recognize a function name by itself. (closes #7770)

src/testdir/test_vim9_cmd.vim

@@ -355,6 +355,25 @@ def Test_method_call_linebreak()
   END
   CheckDefAndScriptSuccess(lines)
 
+  lines =<< trim END
+      new
+      def Foo(): string
+        return 'the text'
+      enddef
+      def Bar(F: func): string
+        return F()
+      enddef
+      def Test()
+        Foo
+          ->Bar()
+          ->setline(1)
+      enddef
+      Test()
+      assert_equal('the text', getline(1))
+      bwipe!
+  END
+  CheckDefAndScriptSuccess(lines)
+
   lines =<< trim END
       new
       g:shortlist

src/testdir/test_vim9_func.vim

@@ -2367,6 +2367,30 @@ def Test_nested_lambda_in_closure()
   delete('XnestedDone')
 enddef
 
+def Test_check_func_arg_types()
+  var lines =<< trim END
+      vim9script
+      def F1(x: string): string
+        return x
+      enddef
+
+      def F2(x: number): number
+        return x + 1
+      enddef
+
+      def G(g: func): dict<func>
+        return {f: g}
+      enddef
+
+      def H(d: dict<func>): string
+        return d.f('a')
+      enddef
+  END
+
+  CheckScriptSuccess(lines + ['echo H(G(F1))'])
+  CheckScriptFailure(lines + ['echo H(G(F2))'], 'E1013:')
+enddef
+
 
 
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/version.c

@@ -750,6 +750,10 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2575,
+/**/
+    2574,
 /**/
     2573,
 /**/

src/vim9compile.c

@@ -386,6 +386,26 @@ variable_exists(char_u *name, size_t len, cctx_T *cctx)
 	    || find_imported(name, len, cctx) != NULL;
 }
 
+/*
+ * Return TRUE if "name" is a local variable, argument, script variable,
+ * imported or function.
+ */
+    static int
+item_exists(char_u *name, size_t len, cctx_T *cctx)
+{
+    int	    is_global;
+
+    if (variable_exists(name, len, cctx))
+	return TRUE;
+
+    // Find a function, so that a following "->" works.  Skip "g:" before a
+    // function name.
+    // Do not check for an internal function, since it might also be a
+    // valid command, such as ":split" versuse "split()".
+    is_global = (name[0] == 'g' && name[1] == ':');
+    return find_func(is_global ? name + 2 : name, is_global, cctx) != NULL;
+}
+
 /*
  * Check if "p[len]" is already defined, either in script "import_sid" or in
  * compilation context "cctx".  "cctx" is NULL at the script level.
@@ -728,7 +748,7 @@ get_compare_isn(exprtype_T exprtype, vartype_T type1, vartype_T type2)
     }
     else if (type1 == VAR_ANY || type2 == VAR_ANY
 	    || ((type1 == VAR_NUMBER || type1 == VAR_FLOAT)
-	      && (type2 == VAR_NUMBER || type2 ==VAR_FLOAT)))
+	      && (type2 == VAR_NUMBER || type2 == VAR_FLOAT)))
 	isntype = ISN_COMPAREANY;
 
     if ((exprtype == EXPR_IS || exprtype == EXPR_ISNOT)
@@ -8399,8 +8419,7 @@ compile_def_function(
 	    }
 	}
 	p = find_ex_command(&ea, NULL, starts_with_colon ? NULL
-		   : (int (*)(char_u *, size_t, cctx_T *))variable_exists,
-									&cctx);
+		    : (int (*)(char_u *, size_t, cctx_T *))item_exists, &cctx);
 
 	if (p == NULL)
 	{

src/vim9execute.c

@@ -797,7 +797,27 @@ call_by_name(char_u *name, int argcount, ectx_T *ectx, isn_T *iptr)
     }
 
     if (ufunc != NULL)
+    {
+	if (ufunc->uf_arg_types != NULL)
+	{
+	    int i;
+	    typval_T	*argv = STACK_TV_BOT(0) - argcount;
+
+	    // The function can change at runtime, check that the argument
+	    // types are correct.
+	    for (i = 0; i < argcount; ++i)
+	    {
+		type_T *type = i < ufunc->uf_args.ga_len
+				  ? ufunc->uf_arg_types[i] : ufunc->uf_va_type;
+
+		if (type != NULL && check_typval_arg_type(type,
+						      &argv[i], i + 1) == FAIL)
+		    return FAIL;
+	    }
+	}
+
 	return call_ufunc(ufunc, NULL, argcount, ectx, iptr);
+    }
 
     return FAIL;
 }