Provide does not satisfy package requirement if package with same name exists

[naderman]

I believe this should be allowed. It works if you swap replace/provide.

{
	"repositories": [
		{
			"packagist": false
		},
		{
			"type": "package",
			"package": [
				{
					"name": "foo/polyfill",
					"provide": {
						"foo/standard": "1.0.0"
					},
					"replace": {
					},
					"version": "1.0.0"
				},
				{
					"name": "foo/standard",
					"require": {
						"foo/does-not-exist": "1.0.0"
					},
					"version": "1.0.0"
				}
			],
			"type": "package"
		}
	],
	"require": {
		"foo/standard": "1.0.0",
		"foo/polyfill": "1.0.0"
	}
}

[naderman]

At least in the current implementation it is very intentional:

composer/src/Composer/DependencyResolver/Pool.php

Lines 271 to 276 in edece86

	// if a package with the required name exists, we ignore providers
	if ($nameMatch) {
	return $matches;
	}
	return array_merge($matches, $provideMatches);

However I think this doesn't hold for extensions being provided by a PHP package, as that array entry is not set for extension names. Which is at the very least inconsistent.