go/types, types2: remove references to under function in comments

Follow-up on CL 712400 which removed the under function.

Change-Id: I253c8adbbaa058150f26e311e37b4c1644b6554d
Reviewed-on: https://go-review.googlesource.com/c/go/+/712520
Reviewed-by: Mark Freeman <markfreeman@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Robert Griesemer <gri@google.com>

Author: Robert Griesemer

src/cmd/compile/internal/types2/call.go

@@ -57,7 +57,7 @@ func (check *Checker) funcInst(T *target, pos syntax.Pos, x *operand, inst *synt
 
 	// Check the number of type arguments (got) vs number of type parameters (want).
 	// Note that x is a function value, not a type expression, so we don't need to
-	// call under below.
+	// call Underlying below.
 	sig := x.typ.(*Signature)
 	got, want := len(targs), sig.TypeParams().Len()
 	if got > want {

src/cmd/compile/internal/types2/infer.go

@@ -427,7 +427,7 @@ func (check *Checker) infer(pos syntax.Pos, tparams []*TypeParam, targs []Type,
 				// Note that if t0 was a signature, t1 must be a signature, and t1
 				// can only be a generic signature if it originated from a generic
 				// function argument. Those signatures are never defined types and
-				// thus there is no need to call under below.
+				// thus there is no need to call Underlying below.
 				// TODO(gri) Consider doing this in Checker.subst.
 				//           Then this would fall out automatically here and also
 				//           in instantiation (where we also explicitly nil out

src/cmd/compile/internal/types2/lookup.go

@@ -145,8 +145,8 @@ func lookupFieldOrMethodImpl(T Type, addressable bool, pkg *Package, name string
 		return // blank fields/methods are never found
 	}
 
-	// Importantly, we must not call under before the call to deref below (nor
-	// does deref call under), as doing so could incorrectly result in finding
+	// Importantly, we must not call Underlying before the call to deref below (nor
+	// does deref call Underlying), as doing so could incorrectly result in finding
 	// methods of the pointer base type when T is a (*Named) pointer type.
 	typ, isPtr := deref(T)
 

src/cmd/compile/internal/types2/named.go

@@ -521,8 +521,8 @@ func (n *Named) Underlying() Type {
 	n.resolve()
 
 	// The gccimporter depends on writing a nil underlying via NewNamed and
-	// immediately reading it back. Rather than putting that in under() and
-	// complicating things there, we just check for that special case here.
+	// immediately reading it back. Rather than putting that in Named.under
+	// and complicating things there, we just check for that special case here.
 	if n.fromRHS == nil {
 		assert(n.allowNilRHS)
 		if n.allowNilUnderlying {

src/cmd/compile/internal/types2/predicates.go

@@ -85,7 +85,7 @@ func isTypeLit(t Type) bool {
 // Safe to call from types that are not fully set up.
 func isTyped(t Type) bool {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	b, _ := t.(*Basic)
 	return b == nil || b.info&IsUntyped == 0
 }
@@ -100,7 +100,7 @@ func isUntyped(t Type) bool {
 // Safe to call from types that are not fully set up.
 func isUntypedNumeric(t Type) bool {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	b, _ := t.(*Basic)
 	return b != nil && b.info&IsUntyped != 0 && b.info&IsNumeric != 0
 }
@@ -519,7 +519,7 @@ func identicalInstance(xorig Type, xargs []Type, yorig Type, yargs []Type) bool
 // for untyped nil is untyped nil.
 func Default(t Type) Type {
 	// Alias and named types cannot denote untyped types
-	// so there's no need to call Unalias or under, below.
+	// so there's no need to call Unalias or Underlying, below.
 	if t, _ := t.(*Basic); t != nil {
 		switch t.kind {
 		case UntypedBool:

src/cmd/compile/internal/types2/unify.go

@@ -779,7 +779,7 @@ func (u *unifier) nify(x, y Type, mode unifyMode, p *ifacePair) (result bool) {
 				}
 				// If y is a defined type, it may not match against cx which
 				// is an underlying type (incl. int, string, etc.). Use assign
-				// mode here so that the unifier automatically takes under(y)
+				// mode here so that the unifier automatically uses y.Underlying()
 				// if necessary.
 				return u.nify(cx, yorig, assign, p)
 			}

src/go/types/call.go

@@ -58,7 +58,7 @@ func (check *Checker) funcInst(T *target, pos token.Pos, x *operand, ix *indexed
 
 	// Check the number of type arguments (got) vs number of type parameters (want).
 	// Note that x is a function value, not a type expression, so we don't need to
-	// call under below.
+	// call Underlying below.
 	sig := x.typ.(*Signature)
 	got, want := len(targs), sig.TypeParams().Len()
 	if got > want {