13 files changed, 147 insertions, 56 deletions
diff --git a/vendor/golang.org/x/crypto/AUTHORS b/vendor/golang.org/x/crypto/AUTHORS
deleted file mode 100644
index 2b00ddba0..000000000
--- a/vendor/golang.org/x/crypto/AUTHORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at https://tip.golang.org/AUTHORS.
diff --git a/vendor/golang.org/x/crypto/CONTRIBUTORS b/vendor/golang.org/x/crypto/CONTRIBUTORS
deleted file mode 100644
index 1fbd3e976..000000000
--- a/vendor/golang.org/x/crypto/CONTRIBUTORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at https://tip.golang.org/CONTRIBUTORS.
diff --git a/vendor/golang.org/x/net/AUTHORS b/vendor/golang.org/x/net/AUTHORS
deleted file mode 100644
index 15167cd74..000000000
--- a/vendor/golang.org/x/net/AUTHORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at http://tip.golang.org/AUTHORS.
diff --git a/vendor/golang.org/x/net/CONTRIBUTORS b/vendor/golang.org/x/net/CONTRIBUTORS
deleted file mode 100644
index 1c4577e96..000000000
--- a/vendor/golang.org/x/net/CONTRIBUTORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.
diff --git a/vendor/golang.org/x/sync/AUTHORS b/vendor/golang.org/x/sync/AUTHORS
deleted file mode 100644
index 15167cd74..000000000
--- a/vendor/golang.org/x/sync/AUTHORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at http://tip.golang.org/AUTHORS.
diff --git a/vendor/golang.org/x/sync/CONTRIBUTORS b/vendor/golang.org/x/sync/CONTRIBUTORS
deleted file mode 100644
index 1c4577e96..000000000
--- a/vendor/golang.org/x/sync/CONTRIBUTORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.
diff --git a/vendor/golang.org/x/tools/AUTHORS b/vendor/golang.org/x/tools/AUTHORS
deleted file mode 100644
index 15167cd74..000000000
--- a/vendor/golang.org/x/tools/AUTHORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at http://tip.golang.org/AUTHORS.
diff --git a/vendor/golang.org/x/tools/CONTRIBUTORS b/vendor/golang.org/x/tools/CONTRIBUTORS
deleted file mode 100644
index 1c4577e96..000000000
--- a/vendor/golang.org/x/tools/CONTRIBUTORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.
diff --git a/vendor/golang.org/x/tools/go/ast/inspector/typeof.go b/vendor/golang.org/x/tools/go/ast/inspector/typeof.go
index 11f4fc369..11ab2bc85 100644
--- a/vendor/golang.org/x/tools/go/ast/inspector/typeof.go
+++ b/vendor/golang.org/x/tools/go/ast/inspector/typeof.go
@@ -77,12 +77,14 @@ const (
 // typeOf returns a distinct single-bit value that represents the type of n.
 //
 // Various implementations were benchmarked with BenchmarkNewInspector:
-//								GOGC=off
-// - type switch				4.9-5.5ms	2.1ms
-// - binary search over a sorted list of types  5.5-5.9ms	2.5ms
-// - linear scan, frequency-ordered list 	5.9-6.1ms	2.7ms
-// - linear scan, unordered list		6.4ms		2.7ms
-// - hash table					6.5ms		3.1ms
+//
+//	                                                                GOGC=off
+//	- type switch					4.9-5.5ms	2.1ms
+//	- binary search over a sorted list of types	5.5-5.9ms	2.5ms
+//	- linear scan, frequency-ordered list		5.9-6.1ms	2.7ms
+//	- linear scan, unordered list			6.4ms		2.7ms
+//	- hash table					6.5ms		3.1ms
+//
 // A perfect hash seemed like overkill.
 //
 // The compiler's switch statement is the clear winner
@@ -90,7 +92,6 @@ const (
 // with constant conditions and good branch prediction.
 // (Sadly it is the most verbose in source code.)
 // Binary search suffered from poor branch prediction.
-//
 func typeOf(n ast.Node) uint64 {
 	// Fast path: nearly half of all nodes are identifiers.
 	if _, ok := n.(*ast.Ident); ok {
diff --git a/vendor/golang.org/x/tools/internal/typeparams/common.go b/vendor/golang.org/x/tools/internal/typeparams/common.go
index ab6b30b83..25a1426d3 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/common.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/common.go
@@ -16,11 +16,10 @@
 // Additionally, this package contains common utilities for working with the
 // new generic constructs, to supplement the standard library APIs. Notably,
 // the StructuralTerms API computes a minimal representation of the structural
-// restrictions on a type parameter. In the future, this API may be available
-// from go/types.
+// restrictions on a type parameter.
 //
-// See the example/README.md for a more detailed guide on how to update tools
-// to support generics.
+// An external version of these APIs is available in the
+// golang.org/x/exp/typeparams module.
 package typeparams
 
 import (
@@ -121,15 +120,15 @@ func OriginMethod(fn *types.Func) *types.Func {
 //
 // For example, consider the following type declarations:
 //
-//  type Interface[T any] interface {
-//  	Accept(T)
-//  }
+//	type Interface[T any] interface {
+//		Accept(T)
+//	}
 //
-//  type Container[T any] struct {
-//  	Element T
-//  }
+//	type Container[T any] struct {
+//		Element T
+//	}
 //
-//  func (c Container[T]) Accept(t T) { c.Element = t }
+//	func (c Container[T]) Accept(t T) { c.Element = t }
 //
 // In this case, GenericAssignableTo reports that instantiations of Container
 // are assignable to the corresponding instantiation of Interface.
diff --git a/vendor/golang.org/x/tools/internal/typeparams/coretype.go b/vendor/golang.org/x/tools/internal/typeparams/coretype.go
new file mode 100644
index 000000000..993135ec9
--- /dev/null
+++ b/vendor/golang.org/x/tools/internal/typeparams/coretype.go
@@ -0,0 +1,122 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package typeparams
+
+import (
+	"go/types"
+)
+
+// CoreType returns the core type of T or nil if T does not have a core type.
+//
+// See https://go.dev/ref/spec#Core_types for the definition of a core type.
+func CoreType(T types.Type) types.Type {
+	U := T.Underlying()
+	if _, ok := U.(*types.Interface); !ok {
+		return U // for non-interface types,
+	}
+
+	terms, err := _NormalTerms(U)
+	if len(terms) == 0 || err != nil {
+		// len(terms) -> empty type set of interface.
+		// err != nil => U is invalid, exceeds complexity bounds, or has an empty type set.
+		return nil // no core type.
+	}
+
+	U = terms[0].Type().Underlying()
+	var identical int // i in [0,identical) => Identical(U, terms[i].Type().Underlying())
+	for identical = 1; identical < len(terms); identical++ {
+		if !types.Identical(U, terms[identical].Type().Underlying()) {
+			break
+		}
+	}
+
+	if identical == len(terms) {
+		// https://go.dev/ref/spec#Core_types
+		// "There is a single type U which is the underlying type of all types in the type set of T"
+		return U
+	}
+	ch, ok := U.(*types.Chan)
+	if !ok {
+		return nil // no core type as identical < len(terms) and U is not a channel.
+	}
+	// https://go.dev/ref/spec#Core_types
+	// "the type chan E if T contains only bidirectional channels, or the type chan<- E or
+	// <-chan E depending on the direction of the directional channels present."
+	for chans := identical; chans < len(terms); chans++ {
+		curr, ok := terms[chans].Type().Underlying().(*types.Chan)
+		if !ok {
+			return nil
+		}
+		if !types.Identical(ch.Elem(), curr.Elem()) {
+			return nil // channel elements are not identical.
+		}
+		if ch.Dir() == types.SendRecv {
+			// ch is bidirectional. We can safely always use curr's direction.
+			ch = curr
+		} else if curr.Dir() != types.SendRecv && ch.Dir() != curr.Dir() {
+			// ch and curr are not bidirectional and not the same direction.
+			return nil
+		}
+	}
+	return ch
+}
+
+// _NormalTerms returns a slice of terms representing the normalized structural
+// type restrictions of a type, if any.
+//
+// For all types other than *types.TypeParam, *types.Interface, and
+// *types.Union, this is just a single term with Tilde() == false and
+// Type() == typ. For *types.TypeParam, *types.Interface, and *types.Union, see
+// below.
+//
+// Structural type restrictions of a type parameter are created via
+// non-interface types embedded in its constraint interface (directly, or via a
+// chain of interface embeddings). For example, in the declaration type
+// T[P interface{~int; m()}] int the structural restriction of the type
+// parameter P is ~int.
+//
+// With interface embedding and unions, the specification of structural type
+// restrictions may be arbitrarily complex. For example, consider the
+// following:
+//
+//  type A interface{ ~string|~[]byte }
+//
+//  type B interface{ int|string }
+//
+//  type C interface { ~string|~int }
+//
+//  type T[P interface{ A|B; C }] int
+//
+// In this example, the structural type restriction of P is ~string|int: A|B
+// expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
+// which when intersected with C (~string|~int) yields ~string|int.
+//
+// _NormalTerms computes these expansions and reductions, producing a
+// "normalized" form of the embeddings. A structural restriction is normalized
+// if it is a single union containing no interface terms, and is minimal in the
+// sense that removing any term changes the set of types satisfying the
+// constraint. It is left as a proof for the reader that, modulo sorting, there
+// is exactly one such normalized form.
+//
+// Because the minimal representation always takes this form, _NormalTerms
+// returns a slice of tilde terms corresponding to the terms of the union in
+// the normalized structural restriction. An error is returned if the type is
+// invalid, exceeds complexity bounds, or has an empty type set. In the latter
+// case, _NormalTerms returns ErrEmptyTypeSet.
+//
+// _NormalTerms makes no guarantees about the order of terms, except that it
+// is deterministic.
+func _NormalTerms(typ types.Type) ([]*Term, error) {
+	switch typ := typ.(type) {
+	case *TypeParam:
+		return StructuralTerms(typ)
+	case *Union:
+		return UnionTermSet(typ)
+	case *types.Interface:
+		return InterfaceTermSet(typ)
+	default:
+		return []*Term{NewTerm(false, typ)}, nil
+	}
+}
diff --git a/vendor/golang.org/x/tools/internal/typeparams/normalize.go b/vendor/golang.org/x/tools/internal/typeparams/normalize.go
index 090f142a5..9c631b651 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/normalize.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/normalize.go
@@ -24,20 +24,22 @@ var ErrEmptyTypeSet = errors.New("empty type set")
 // Structural type restrictions of a type parameter are created via
 // non-interface types embedded in its constraint interface (directly, or via a
 // chain of interface embeddings). For example, in the declaration
-//  type T[P interface{~int; m()}] int
+//
+//	type T[P interface{~int; m()}] int
+//
 // the structural restriction of the type parameter P is ~int.
 //
 // With interface embedding and unions, the specification of structural type
 // restrictions may be arbitrarily complex. For example, consider the
 // following:
 //
-//  type A interface{ ~string|~[]byte }
+//	type A interface{ ~string|~[]byte }
 //
-//  type B interface{ int|string }
+//	type B interface{ int|string }
 //
-//  type C interface { ~string|~int }
+//	type C interface { ~string|~int }
 //
-//  type T[P interface{ A|B; C }] int
+//	type T[P interface{ A|B; C }] int
 //
 // In this example, the structural type restriction of P is ~string|int: A|B
 // expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
diff --git a/vendor/golang.org/x/tools/internal/typeparams/termlist.go b/vendor/golang.org/x/tools/internal/typeparams/termlist.go
index 10857d504..933106a23 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/termlist.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/termlist.go
@@ -97,15 +97,6 @@ func (xl termlist) norm() termlist {
 	return rl
 }
 
-// If the type set represented by xl is specified by a single (non-𝓤) term,
-// structuralType returns that type. Otherwise it returns nil.
-func (xl termlist) structuralType() types.Type {
-	if nl := xl.norm(); len(nl) == 1 {
-		return nl[0].typ // if nl.isAll() then typ is nil, which is ok
-	}
-	return nil
-}
-
 // union returns the union xl ∪ yl.
 func (xl termlist) union(yl termlist) termlist {
 	return append(xl, yl...).norm()