This test verifies spurious pkgname conflicts.
Issue golang/go#67069.

-- go.mod --
module example
go 1.19

-- aa/a.go --
package aa

var cc int //@rename("cc", "aa", CToA)
const C = 0
const D = 0

-- aa/a_test.go --
package aa_test

import "example/aa"

var _ = aa.C //@rename("aa", "bb", AToB)
-- @CToA/aa/a.go --
@@ -3 +3 @@
-var cc int //@rename("cc", "aa", CToA)
+var aa int //@rename("cc", "aa", CToA)
-- @AToB/aa/a_test.go --
@@ -3 +3 @@
-import "example/aa"
+import bb "example/aa"
@@ -5 +5 @@
-var _ = aa.C //@rename("aa", "bb", AToB)
+var _ = bb.C //@rename("aa", "bb", AToB)
-- bb/b.go --
package bb

import "example/aa"

var _ = aa.C
var bb int //@renameerr("bb", "aa", errImportConflict)

-- @errImportConflict --
bb/b.go:6:5: renaming this var "bb" to "aa" would conflict
bb/b.go:3:8:	with this imported package name
-- aa/a_internal_test.go --
package aa

var _ = D //@rename("D", "aa", DToA)
-- @DToA/aa/a_internal_test.go --
@@ -3 +3 @@
-var _ = D //@rename("D", "aa", DToA)
+var _ = aa //@rename("D", "aa", DToA)
-- @DToA/aa/a.go --
@@ -5 +5 @@
-const D = 0
+const aa = 0