go/types: remove work-around for issue #26390

This work-around is not needed anymore now that method
signatures are type-checked separately from their receiver
base types: no artificial cycles are introduced anymore
and so there is no need to artificially cut them.

Fixes #26854.

Change-Id: I2ef15ceeaa0b486f65f6cdc466d0cf06246c74d7
Reviewed-on: https://go-review.googlesource.com/c/139900
Reviewed-by: Alan Donovan <adonovan@google.com>

diff --git a/src/go/types/decl.go b/src/go/types/decl.go
index 3d8054de2390f4f28c0a9c7fe5ebc9fdd3a02bb9..1e2790a1711cf5d86da2d5dc66c6c060fcc54cce 100644 (file)
--- a/src/go/types/decl.go
+++ b/src/go/types/decl.go
@@ -150,31 +150,6 @@ func (check *Checker) objDecl(obj Object, def *Named) {
                        }
 
                case *TypeName:
-                       // fixFor26390 enables a temporary work-around to handle alias type names
-                       // that have not been given a type yet even though the underlying type
-                       // is already known. See testdata/issue26390.src for a simple example.
-                       // Set this flag to false to disable this code quickly (and comment
-                       // out the new test in decls4.src that will fail again).
-                       // TODO(gri) remove this for Go 1.12 in favor of a more comprehensive fix
-                       const fixFor26390 = true
-                       if fixFor26390 {
-                               // If we have a package-level alias type name that has not been
-                               // given a type yet but the underlying type is a type name that
-                               // has been given a type already, don't report a cycle but use
-                               // the underlying type name's type instead. The cycle shouldn't
-                               // exist in the first place in this case and is due to the way
-                               // methods are type-checked at the moment. See also the comment
-                               // at the end of Checker.typeDecl below.
-                               if d := check.objMap[obj]; d != nil && d.alias && obj.typ == Typ[Invalid] {
-                                       // If we can find the underlying type name syntactically
-                                       // and it has a type, use that type.
-                                       if tname := check.resolveBaseTypeName(ast.NewIdent(obj.name)); tname != nil && tname.typ != nil {
-                                               obj.typ = tname.typ
-                                               break
-                                       }
-                               }
-                       }
-
                        if check.typeCycle(obj) {
                                // break cycle
                                // (without this, calling underlying()