From: Alberto Donizetti <alb.donizetti@gmail.com>
Date: Fri, 20 Mar 2020 18:13:07 +0000 (+0100)
Subject: math/big: document that Sqrt doesn't set Accuracy
X-Git-Tag: go1.15beta1~806
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c5058652fd724cb1ed8ea91a4e76b202d6910482;p=gostls13.git

math/big: document that Sqrt doesn't set Accuracy

Document that the Float.Sqrt method does not set the receiver's
Accuracy field.

Updates #37915

Change-Id: Ief1dcac07eacc0ef02f86bfac9044501477bca1c
Reviewed-on: https://go-review.googlesource.com/c/go/+/224497
Reviewed-by: Robert Griesemer <gri@golang.org>
---

diff --git a/src/math/big/float.go b/src/math/big/float.go
index b3c3295201..da964eef3e 100644
--- a/src/math/big/float.go
+++ b/src/math/big/float.go
@@ -224,7 +224,9 @@ func (x *Float) Mode() RoundingMode {
 	return x.mode
 }
 
-// Acc returns the accuracy of x produced by the most recent operation.
+// Acc returns the accuracy of x produced by the most recent
+// operation, unless explicitly documented otherwise by that
+// operation.
 func (x *Float) Acc() Accuracy {
 	return x.acc
 }
diff --git a/src/math/big/sqrt.go b/src/math/big/sqrt.go
index 53403aa41d..ac2094f28e 100644
--- a/src/math/big/sqrt.go
+++ b/src/math/big/sqrt.go
@@ -14,7 +14,8 @@ var (
 //
 // If z's precision is 0, it is changed to x's precision before the
 // operation. Rounding is performed according to z's precision and
-// rounding mode.
+// rounding mode, but z's accuracy is not computed. Specifically, the
+// result of z.Acc() is undefined.
 //
 // The function panics if z < 0. The value of z is undefined in that
 // case.