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digitalmars.D.learn - Undescriptive linker error. (bug?)

reply Sjoerd Nijboer <dlang sjoerdnijboer.com> writes:
module mymodule;

class Foo{}

Foo Bar()
{
	Foo foo();
	
	return foo;
}

int main()
{
	auto foo = Bar();

     return 0;
}

This code doesn't compile with a linker error that there's a 
missing symbol for `Foo Bar()` on windows.
After all, `Foo foo();` isn't legitimate D.
But why does it return a linker error?
shouldn't it give an error that is more descriptive about a class 
instance being wrong?
I feel like this would be a common thing people try to write.
Especially in templates this would become difficult to narrow 
down.
Apr 05
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Friday, 5 April 2019 at 21:59:35 UTC, Sjoerd Nijboer wrote:
 Foo Bar()
 {
 	Foo foo();
It looks like the compiler is treating that as a function prototype without a body (that just happens to be nested in another function).
 	return foo;
And then, this foo is given the optional parens treatment, as if it was a call to foo() of the given function, which is why the linker complains. Weird combination of cases that maybe should be illegal.
Apr 05
parent Sjoerd Nijboer <dlang sjoerdnijboer.com> writes:
On Friday, 5 April 2019 at 22:08:50 UTC, Adam D. Ruppe wrote:
 Weird combination of cases that maybe should be illegal.
It errors with the highly descriptive errormessage: app.obj(app) Error 42: Symbol Undefined __D8mymodule3BarFZ3fooMFZCQx3Foo Error: linker exited with status 1
Apr 05