diff --git a/module/module.go b/module/module.go
index 3a8b080..77d6f8e 100644
--- a/module/module.go
+++ b/module/module.go
@@ -225,13 +225,13 @@
 }
 
 // pathOK reports whether r can appear in an import path element.
-// Paths can be ASCII letters, ASCII digits, and limited ASCII punctuation: + - . _ and ~.
+// Paths can be ASCII letters, ASCII digits, and limited ASCII punctuation: - . _ and ~.
 // This matches what "go get" has historically recognized in import paths.
 // TODO(rsc): We would like to allow Unicode letters, but that requires additional
 // care in the safe encoding (see "escaped paths" above).
 func pathOK(r rune) bool {
 	if r < utf8.RuneSelf {
-		return r == '+' || r == '-' || r == '.' || r == '_' || r == '~' ||
+		return r == '-' || r == '.' || r == '_' || r == '~' ||
 			'0' <= r && r <= '9' ||
 			'A' <= r && r <= 'Z' ||
 			'a' <= r && r <= 'z'
@@ -314,7 +314,7 @@
 // separated by slashes (U+002F). (It must not begin with nor end in a slash.)
 //
 // A valid path element is a non-empty string made up of
-// ASCII letters, ASCII digits, and limited ASCII punctuation: + - . _ and ~.
+// ASCII letters, ASCII digits, and limited ASCII punctuation: - . _ and ~.
 // It must not begin or end with a dot (U+002E), nor contain two dots in a row.
 //
 // The element prefix up to the first dot must not be a reserved file name
diff --git a/module/module_test.go b/module/module_test.go
index 1a6115f..8e56749 100644
--- a/module/module_test.go
+++ b/module/module_test.go
@@ -104,7 +104,7 @@
 	{"x.y(/z", false, false, true},
 	{"x.y)/z", false, false, true},
 	{"x.y*/z", false, false, false},
-	{"x.y+/z", false, true, true},
+	{"x.y+/z", false, false, true},
 	{"x.y,/z", false, false, true},
 	{"x.y-/z", true, true, true},
 	{"x.y./zt", false, false, false},
@@ -134,7 +134,7 @@
 	{"x.y/z(", false, false, true},
 	{"x.y/z)", false, false, true},
 	{"x.y/z*", false, false, false},
-	{"x.y/z+", true, true, true},
+	{"x.y/z+", false, false, true},
 	{"x.y/z,", false, false, true},
 	{"x.y/z-", true, true, true},
 	{"x.y/z.t", true, true, true},
@@ -241,7 +241,7 @@
 	path string
 	esc  string // empty means same as path
 }{
-	{path: "ascii.com/abcdefghijklmnopqrstuvwxyz.-+/~_0123456789"},
+	{path: "ascii.com/abcdefghijklmnopqrstuvwxyz.-/~_0123456789"},
 	{path: "github.com/GoogleCloudPlatform/omega", esc: "github.com/!google!cloud!platform/omega"},
 }