go/parser: remove unused method checkBinaryExpr

Change-Id: Ica981657e50e30cbfa1757e8457819a479f11c7d
Reviewed-on: https://go-review.googlesource.com/c/go/+/412775
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>

src/go/parser/parser.go

@@ -1821,23 +1821,6 @@ func (p *parser) parseBinaryExpr(x ast.Expr, prec1 int, check bool) ast.Expr {
 	}
 }
 
-// checkBinaryExpr checks binary expressions that were not already checked by
-// parseBinaryExpr, because the latter was called with check=false.
-func (p *parser) checkBinaryExpr(x ast.Expr) {
-	bx, ok := x.(*ast.BinaryExpr)
-	if !ok {
-		return
-	}
-
-	bx.X = p.checkExpr(bx.X)
-	bx.Y = p.checkExpr(bx.Y)
-
-	// parseBinaryExpr checks x and y for each binary expr in a tree, so we
-	// traverse the tree of binary exprs starting from x.
-	p.checkBinaryExpr(bx.X)
-	p.checkBinaryExpr(bx.Y)
-}
-
 // The result may be a type or even a raw type ([...]int). Callers must
 // check the result (using checkExpr or checkExprOrType), depending on
 // context.