是什么导致了这个 Ada 编译错误 "ambiguous character literal"？

Question

我有这个 Ada 代码。

with Ada.Text_IO; 
use Ada.Text_IO;

procedure for_Loop is
begin
    for Counter in 'A'..'Z' loop
        Put(Counter);   
    end loop;
    New_Line;
end for_Loop;

Ada 编译器 (gnatmake) 输出这些错误消息。

gcc -c for_loop.adb
for_loop.adb:6:24: ambiguous character literal
for_loop.adb:6:24: possible interpretation: Character
for_loop.adb:6:24: possible interpretation: Wide_Character
for_loop.adb:6:24: possible interpretation: Wide_Wide_Character
gnatmake: "for_loop.adb" compilation error

代码有什么问题？

Answer 1

来自this post：

The problem is that 'A' and 'Z' could be from either Character or Wide_Character. The simplest correction is to make the type explicit; e.g.: for Char in Character range 'A' .. 'Z' loop ... end loop;

with Ada.Text_IO; 
use Ada.Text_IO;

procedure for_Loop is
begin
    for Counter in Character range 'A'..'Z' loop
        Put(Counter);   
    end loop;
    New_Line;
end for_Loop;

这是输出：

ABCDEFGHIJKLMNOPQRSTUVWXYZ

是什么导致了这个 Ada 编译错误 "ambiguous character literal"？

What caused this Ada compilation error "ambiguous character literal"?

ada

gnat