template mixins allows to declare duplicates

[dlangBugzillaToGithub]

Temtaime (@Temtaime) reported this on 2014-08-31T11:07:45Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=13408

Description

import std.stdio;

mixin template R() {
	~this() { write(1); }
}

struct S {
	mixin R;

	~this() { write(2); }
}

void main() {
	S s;
}

This code compiles OK and prints 21 when it should NOT.

import std.stdio;

mixin template R() {
	int a = 1;
	void foo() { write(a); }
}

struct S {
	mixin R;

	void bar() { write(a); }

	int a = 2;
}

void main() {
	S s;
	s.foo();
	s.bar();
}

This code also compiles OK and prints 12 when it's strange and bug-prone.

[dlangBugzillaToGithub]

temtaime commented on 2014-09-01T11:50:45Z

There's one another issue.

mixin template R() {
	void foo() { writeln(1); }
	void foo() { writeln(2); }
}

struct S {
	mixin R;
}

void main() {
	S s;
}

This code compiles OK, but linker error.