Fix Issue 18809 - Improve error message on nonexistent property

[alexandrumc]

The current ”no property” error message does not provide information about the module where the type in question is defined, so I added this information.

The module in which a symbol is defined will be printed only for the symbols which are defined in a file and misused somewhere else. This means that for this example

struct SomeStruct {}

void main() {
    auto s = SomeStruct();
    s.nonexistent = "hello";
}

the compiler will yield "Error: no property nonexistent for type SomeStruct"

while for this example

import core.memory;
enum e = GC.foo;

the compiler will yield "Error: no property foo for type core.memory.GC"

Templates were not included in this solution since their fully qualified names may get very complicated. Moreover, I observed that sometimes the basic names of the symbols are already fully qualified (for reference:

dmd/test/fail_compilation/test15897.d

Line 5 in 57cd63e

fail_compilation/test15897.d(18): Error: no property `create` for type `imports.test15897.Cat`

and

dmd/test/fail_compilation/test12228.d

Line 6 in 57cd63e

fail_compilation/test12228.d(19): Error: no property `x` for type `object.Object`

so I added a check to avoid printing the same information twice.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	18809	enhancement	Improve error message on nonexistent property

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + dmd#10604"

[marler8997]

else
{

[marler8997]

It looks like this whole block can be factored into a function:

error(loc, "no property `%s` for type `%s%s`", ident.toChars(), tryGetModuleQualifier(mt), mt.toChars()))

// somewhere else
string tryGetModuleQualfier(Type mt)
{
    // try to create and return a string to qualify mt
}

[RazvanN7]

We don't need to special case. Either we output the fully qualified name at all times or we don't.

In this situation it is better to output the fully qualified name even if it results in verbose outputs in the case of template instances. Fully qualified names offer the full information about where the type is declared and also, in the case of template instances, the instantiation types.

[RazvanN7]

Minus the mentioned nit

[PetarKirov]

Perhaps we should special case Voldemort types in error messages after all.

[PetarKirov]

BTW, the type of errors that one typically gets when missing std.algorithm / std.range imports are surprisingly underrepresented in the dmd test suite.

[atilaneves]

I'm not sure we should. At least with this change you'd know where to look to find the specific Voldermort type.

[RazvanN7]

If you do that, in this particular situation, if you instantiate with another type (other than int) you would have the same error message at the same line, giving you no hint at all. With this patch you will have additional information(with what types the template has been instantiated). Ideally, the instantiation location should also be outputted, but I think that this should be the topic of a different PR.

[PetarKirov]

To be honest, I didn't check the test case in question. I assumed that it follows a typical phobos Voldemort pattern, but there are no Voldemort types involved at all. Disregard my comment.