cmd/compile/internal/types2: use a TypeList type to hold type arguments

This is a port of CL 343933 from go/types with the necessary
adjustments in the compiler.

With this CL type parameters and type lists are now held in
TParamList and TypeList data types which don't expose the
internal representation.

Change-Id: I6d60881b5db995dbc04ed3f4a96e8b5d41f83969
Reviewed-on: https://go-review.googlesource.com/c/go/+/344615
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dan Scales <danscales@google.com>

1 files changed, 0 insertions, 34 deletions

diff --git a/src/cmd/compile/internal/types2/typeparam.go b/src/cmd/compile/internal/types2/typeparam.go
index 0d76dd1a6e..445337fee8 100644
--- a/src/cmd/compile/internal/types2/typeparam.go
+++ b/src/cmd/compile/internal/types2/typeparam.go
@@ -83,40 +83,6 @@ func (t *TypeParam) SetConstraint(bound Type) {
 func (t *TypeParam) Underlying() Type { return t }
 func (t *TypeParam) String() string   { return TypeString(t, nil) }
 
-// TParamList holds a list of type parameters bound to a type.
-type TParamList struct{ tparams []*TypeParam }
-
-// Len returns the number of type parameters in the list.
-// It is safe to call on a nil receiver.
-func (tps *TParamList) Len() int {
-	return len(tps.list())
-}
-
-// At returns the i'th type parameter in the list.
-func (tps *TParamList) At(i int) *TypeParam {
-	return tps.list()[i]
-}
-
-func (tps *TParamList) list() []*TypeParam {
-	if tps == nil {
-		return nil
-	}
-	return tps.tparams
-}
-
-func bindTParams(list []*TypeParam) *TParamList {
-	if len(list) == 0 {
-		return nil
-	}
-	for i, typ := range list {
-		if typ.index >= 0 {
-			panic("type parameter bound more than once")
-		}
-		typ.index = i
-	}
-	return &TParamList{tparams: list}
-}
-
 // ----------------------------------------------------------------------------
 // Implementation