compiler: reword "declared and not used" error message

This is a gofrontend copy of https://golang.org/cl/203282.

From the CL 203282 description:

    "declared and not used" is technically correct, but might confuse
    the user. Switching "and" to "but" will hopefully create the
    contrast for the users: they did one thing (declaration), but
    not the other --- actually using the variable.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/273629

5 files changed, 8 insertions, 18 deletions

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index d6ee857..183e5ca 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-720b8fed93143f284ca04358e1b13c8a3487281e
+6b01f8cdc11d86bd98165c91d6ae101bcf6b9e1a
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
diff --git a/gcc/go/gofrontend/gogo.cc b/gcc/go/gofrontend/gogo.cc
index 93a4a57..a5e4521 100644
--- a/gcc/go/gofrontend/gogo.cc
+++ b/gcc/go/gofrontend/gogo.cc
@@ -3744,7 +3744,7 @@ Check_types_traverse::variable(Named_object* named_object)
           && !var->type()->is_error()
           && (init == NULL || !init->is_error_expression())
           && !Lex::is_invalid_identifier(named_object->name()))
-	go_error_at(var->location(), "%qs declared and not used",
+	go_error_at(var->location(), "%qs declared but not used",
 		    named_object->message_name().c_str());
     }
   return TRAVERSE_CONTINUE;
diff --git a/gcc/go/gofrontend/parse.cc b/gcc/go/gofrontend/parse.cc
index 00ac2f8..b1925ed 100644
--- a/gcc/go/gofrontend/parse.cc
+++ b/gcc/go/gofrontend/parse.cc
@@ -4817,7 +4817,7 @@ Parse::type_switch_body(Label* label, const Type_switch& type_switch,
 	    }
 	}
       if (!used)
-	go_error_at(type_switch.location, "%qs declared and not used",
+	go_error_at(type_switch.location, "%qs declared but not used",
 		    Gogo::message_name(var_name).c_str());
     }
   return statement;
diff --git a/gcc/testsuite/go.test/test/fixedbugs/bug373.go b/gcc/testsuite/go.test/test/fixedbugs/bug373.go
index e91f26d..6b7a312 100644
--- a/gcc/testsuite/go.test/test/fixedbugs/bug373.go
+++ b/gcc/testsuite/go.test/test/fixedbugs/bug373.go
@@ -1,6 +1,6 @@
 // errorcheck
 
-// Copyright 2011 The Go Authors.  All rights reserved.
+// Copyright 2011 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
@@ -9,7 +9,7 @@
 package foo
 
 func f(x interface{}) {
-	switch t := x.(type) {  // ERROR "declared and not used"
+	switch t := x.(type) {  // ERROR "declared but not used"
 	case int:
 	}
 }
diff --git a/gcc/testsuite/go.test/test/typeswitch2.go b/gcc/testsuite/go.test/test/typeswitch2.go
index 6c70307..62c96c8 100644
--- a/gcc/testsuite/go.test/test/typeswitch2.go
+++ b/gcc/testsuite/go.test/test/typeswitch2.go
@@ -4,7 +4,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Verify that various erroneous type switches are caught be the compiler.
+// Verify that various erroneous type switches are caught by the compiler.
 // Does not compile.
 
 package main
@@ -26,22 +26,12 @@ func whatis(x interface{}) string {
 		w()
 	}:
 		return "rw"
-	case interface {	// GCCGO_ERROR "duplicate"
+	case interface {	// ERROR "duplicate"
 		w()
 		r()
-	}: // GC_ERROR "duplicate"
+	}:
 		return "wr"
 
 	}
 	return ""
 }
-
-func notused(x interface{}) {
-	// The first t is in a different scope than the 2nd t; it cannot
-	// be accessed (=> declared and not used error); but it is legal
-	// to declare it.
-	switch t := 0; t := x.(type) { // ERROR "declared and not used"
-	case int:
-		_ = t // this is using the t of "t := x.(type)"
-	}
-}