[enh] Issue 12567 - Modules can't be marked as deprecated

[9rnsr]

https://issues.dlang.org/show_bug.cgi?id=12567

Points:

1. Compiler checks the deprecation when the module is imported.

   deprecated("std.regexp is deprecated. Please use std.regex instead.")
   module std.regexp

   module test;
   import std.regexp;  // This line will report the message

2. ModuleDeclaraion is necessary if you want to make the module deprecated.

3. Deprecating a module does not deprecate its members automatically.

   It's useful if you want to merely rename modules.

   deprecated("std.regexp is renamed to std.regex.")
   module std.regexp;
   /* All members are not implicitly marked as deprecated */

   module std.regex;
   /* Exactly same contents with in std.regexp. */

[MartinNowak]

Auto-merge toggled on

[ghost]

Excellent. However, won't this require a change in the lexer spec? AFAIK the very first thing in a module should either be a shebang or the module declaration, so a deprecated statement should also be added as a possibility.

[IgorStepanov]

@9rnsr Great enhancement. BTW, do you plan to allow other attributes for module? I tell about language attributes like @safe or @nogs and about UDAs. UDAs for modules and function arguments can significantly extend UDAs programming opportunities.

[MartinNowak]

Excellent. However, won't this require a change in the lexer spec? AFAIK the very first thing in a module should either be a shebang or the module declaration, so a deprecated statement should also be added as a possibility.

What dmd relies on is that the first letter in any source code must be an ASCII character.
This is used to determine the file encoding (UTF-8, UTF16...) and it still works with a deprecated module declaration.

[9rnsr]

@IgorStepanov I opened documentation fix: dlang/dlang.org#642

[yebblies]

Hmm ok.

1. The error message is not suppressed when one deprecated module imports another.
2. Import statements don't give an error.
3. Imports inside deprecated declarations don't suppress the error.

[IgorStepanov]

@9rnsr I asked about UDAs for modules like

@BindModule("foobar") @safe module foo.bar;
...
pragma(msg, __traits(getAttributes, foo.bar));

... and about function parameter attributes:

void foo(@BindParam("A") int a, @BindParam("B") int b){}
...
pragma(msg, __traits(getArgumentAttributes, foo, 0)); //a attributes
pragma(msg, __traits(getArgumentAttributes, foo, 1)); //b attributes

[9rnsr]

@IgorStepanov If you want to request new language feature, please file it in bugzilla with reasonable use cases.