go/ast: rename MultiIndexExpr to IndexListExpr

As discussed in #47781, IndexListExpr is one character shorter and has
the advantage of being next to IndexExpr in documentation.

Updates #47781

Change-Id: I709d5c1a79b4f9aebcd6445e4ab0cd6dae45bab7
Reviewed-on: https://go-review.googlesource.com/c/go/+/348609
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>

src/go/ast/ast.go

@@ -344,9 +344,9 @@ type (
 		Rbrack token.Pos // position of "]"
 	}
 
-	// A MultiIndexExpr node represents an expression followed by multiple
+	// An IndexListExpr node represents an expression followed by multiple
 	// indices.
-	MultiIndexExpr struct {
+	IndexListExpr struct {
 		X       Expr      // expression
 		Lbrack  token.Pos // position of "["
 		Indices []Expr    // index expressions
@@ -496,7 +496,7 @@ func (x *CompositeLit) Pos() token.Pos {
 func (x *ParenExpr) Pos() token.Pos      { return x.Lparen }
 func (x *SelectorExpr) Pos() token.Pos   { return x.X.Pos() }
 func (x *IndexExpr) Pos() token.Pos      { return x.X.Pos() }
-func (x *MultiIndexExpr) Pos() token.Pos { return x.X.Pos() }
+func (x *IndexListExpr) Pos() token.Pos  { return x.X.Pos() }
 func (x *SliceExpr) Pos() token.Pos      { return x.X.Pos() }
 func (x *TypeAssertExpr) Pos() token.Pos { return x.X.Pos() }
 func (x *CallExpr) Pos() token.Pos       { return x.Fun.Pos() }
@@ -530,7 +530,7 @@ func (x *CompositeLit) End() token.Pos   { return x.Rbrace + 1 }
 func (x *ParenExpr) End() token.Pos      { return x.Rparen + 1 }
 func (x *SelectorExpr) End() token.Pos   { return x.Sel.End() }
 func (x *IndexExpr) End() token.Pos      { return x.Rbrack + 1 }
-func (x *MultiIndexExpr) End() token.Pos { return x.Rbrack + 1 }
+func (x *IndexListExpr) End() token.Pos  { return x.Rbrack + 1 }
 func (x *SliceExpr) End() token.Pos      { return x.Rbrack + 1 }
 func (x *TypeAssertExpr) End() token.Pos { return x.Rparen + 1 }
 func (x *CallExpr) End() token.Pos       { return x.Rparen + 1 }
@@ -562,7 +562,7 @@ func (*CompositeLit) exprNode()   {}
 func (*ParenExpr) exprNode()      {}
 func (*SelectorExpr) exprNode()   {}
 func (*IndexExpr) exprNode()      {}
-func (*MultiIndexExpr) exprNode() {}
+func (*IndexListExpr) exprNode()  {}
 func (*SliceExpr) exprNode()      {}
 func (*TypeAssertExpr) exprNode() {}
 func (*CallExpr) exprNode()       {}

src/go/ast/walk.go

@@ -116,7 +116,7 @@ func Walk(v Visitor, node Node) {
 		Walk(v, n.X)
 		Walk(v, n.Index)
 
-	case *MultiIndexExpr:
+	case *IndexListExpr:
 		Walk(v, n.X)
 		for _, index := range n.Indices {
 			Walk(v, index)

src/go/internal/typeparams/typeparams.go

@@ -21,7 +21,7 @@ func PackIndexExpr(x ast.Expr, lbrack token.Pos, exprs []ast.Expr, rbrack token.
 			Rbrack: rbrack,
 		}
 	default:
-		return &ast.MultiIndexExpr{
+		return &ast.IndexListExpr{
 			X:       x,
 			Lbrack:  lbrack,
 			Indices: exprs,
@@ -30,25 +30,24 @@ func PackIndexExpr(x ast.Expr, lbrack token.Pos, exprs []ast.Expr, rbrack token.
 	}
 }
 
-// IndexExpr wraps an ast.IndexExpr or ast.MultiIndexExpr into the
-// MultiIndexExpr interface.
+// IndexExpr wraps an ast.IndexExpr or ast.IndexListExpr.
 //
 // Orig holds the original ast.Expr from which this IndexExpr was derived.
 type IndexExpr struct {
-	Orig ast.Expr // the wrapped expr, which may be distinct from MultiIndexExpr below.
-	*ast.MultiIndexExpr
+	Orig ast.Expr // the wrapped expr, which may be distinct from the IndexListExpr below.
+	*ast.IndexListExpr
 }
 
 func UnpackIndexExpr(n ast.Node) *IndexExpr {
 	switch e := n.(type) {
 	case *ast.IndexExpr:
-		return &IndexExpr{e, &ast.MultiIndexExpr{
+		return &IndexExpr{e, &ast.IndexListExpr{
 			X:       e.X,
 			Lbrack:  e.Lbrack,
 			Indices: []ast.Expr{e.Index},
 			Rbrack:  e.Rbrack,
 		}}
-	case *ast.MultiIndexExpr:
+	case *ast.IndexListExpr:
 		return &IndexExpr{e, e}
 	}
 	return nil

src/go/parser/parser.go

@@ -1570,7 +1570,7 @@ func (p *parser) checkExpr(x ast.Expr) ast.Expr {
 		panic("unreachable")
 	case *ast.SelectorExpr:
 	case *ast.IndexExpr:
-	case *ast.MultiIndexExpr:
+	case *ast.IndexListExpr:
 	case *ast.SliceExpr:
 	case *ast.TypeAssertExpr:
 		// If t.Type == nil we have a type assertion of the form
@@ -1660,7 +1660,7 @@ func (p *parser) parsePrimaryExpr() (x ast.Expr) {
 					return
 				}
 				// x is possibly a composite literal type
-			case *ast.IndexExpr, *ast.MultiIndexExpr:
+			case *ast.IndexExpr, *ast.IndexListExpr:
 				if p.exprLev < 0 {
 					return
 				}

src/go/printer/nodes.go

@@ -873,7 +873,7 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int) {
 		p.expr0(x.Index, depth+1)
 		p.print(x.Rbrack, token.RBRACK)
 
-	case *ast.MultiIndexExpr:
+	case *ast.IndexListExpr:
 		// TODO(gri): as for IndexExpr, should treat [] like parentheses and undo
 		// one level of depth
 		p.expr1(x.X, token.HighestPrec, 1)

src/go/types/call.go

@@ -337,7 +337,7 @@ func (check *Checker) arguments(call *ast.CallExpr, sig *Signature, targs []Type
 	if sig.TypeParams().Len() > 0 {
 		if !check.allowVersion(check.pkg, 1, 18) {
 			switch call.Fun.(type) {
-			case *ast.IndexExpr, *ast.MultiIndexExpr:
+			case *ast.IndexExpr, *ast.IndexListExpr:
 				ix := typeparams.UnpackIndexExpr(call.Fun)
 				check.softErrorf(inNode(call.Fun, ix.Lbrack), _Todo, "function instantiation requires go1.18 or later")
 			default:

src/go/types/expr.go

@@ -1392,7 +1392,7 @@ func (check *Checker) exprInternal(x *operand, e ast.Expr, hint Type) exprKind {
 	case *ast.SelectorExpr:
 		check.selector(x, e)
 
-	case *ast.IndexExpr, *ast.MultiIndexExpr:
+	case *ast.IndexExpr, *ast.IndexListExpr:
 		ix := typeparams.UnpackIndexExpr(e)
 		if check.indexExpr(x, ix) {
 			check.funcInst(x, ix)

src/go/types/exprstring.go

@@ -67,7 +67,7 @@ func WriteExpr(buf *bytes.Buffer, x ast.Expr) {
 		buf.WriteByte('.')
 		buf.WriteString(x.Sel.Name)
 
-	case *ast.IndexExpr, *ast.MultiIndexExpr:
+	case *ast.IndexExpr, *ast.IndexListExpr:
 		ix := typeparams.UnpackIndexExpr(x)
 		WriteExpr(buf, ix.X)
 		buf.WriteByte('[')

src/go/types/resolver.go

@@ -513,7 +513,7 @@ L: // unpack receiver type
 
 	// unpack type parameters, if any
 	switch rtyp.(type) {
-	case *ast.IndexExpr, *ast.MultiIndexExpr:
+	case *ast.IndexExpr, *ast.IndexListExpr:
 		ix := typeparams.UnpackIndexExpr(rtyp)
 		rtyp = ix.X
 		if unpackParams {

src/go/types/signature.go

@@ -326,7 +326,7 @@ func isubst(x ast.Expr, smap map[*ast.Ident]*ast.Ident) ast.Expr {
 			new.X = X
 			return &new
 		}
-	case *ast.IndexExpr, *ast.MultiIndexExpr:
+	case *ast.IndexExpr, *ast.IndexListExpr:
 		ix := typeparams.UnpackIndexExpr(x)
 		var newIndexes []ast.Expr
 		for i, index := range ix.Indices {

src/go/types/struct.go

@@ -176,7 +176,7 @@ func embeddedFieldIdent(e ast.Expr) *ast.Ident {
 		return e.Sel
 	case *ast.IndexExpr:
 		return embeddedFieldIdent(e.X)
-	case *ast.MultiIndexExpr:
+	case *ast.IndexListExpr:
 		return embeddedFieldIdent(e.X)
 	}
 	return nil // invalid embedded field

src/go/types/typexpr.go

@@ -258,7 +258,7 @@ func (check *Checker) typInternal(e0 ast.Expr, def *Named) (T Type) {
 			check.errorf(&x, _NotAType, "%s is not a type", &x)
 		}
 
-	case *ast.IndexExpr, *ast.MultiIndexExpr:
+	case *ast.IndexExpr, *ast.IndexListExpr:
 		ix := typeparams.UnpackIndexExpr(e)
 		if !check.allowVersion(check.pkg, 1, 18) {
 			check.softErrorf(inNode(e, ix.Lbrack), _Todo, "type instantiation requires go1.18 or later")