BUG #8210: UTF8 column names corrupted by server

The following bug has been logged on the website:

Bug reference: 8210
Logged by: Martin Schaefer
Email address: martin(dot)schaefer(at)cadcorp(dot)com
PostgreSQL version: 9.2.1
Operating system: Windows 8
Description:

The following code:

const wchar_t *strName = L"id_äß";
wstring strCreate = wstring(L"create table test_umlaut(") + strName + L"
integer primary key)";

PGconn *pConn = PQsetdbLogin("", "", NULL, NULL, "dev503", "postgres",
"******");
if (!pConn) FAIL;
if (PQsetClientEncoding(pConn, "UTF-8")) FAIL;

PGresult *pResult = PQexec(pConn, "drop table test_umlaut");
if (pResult) PQclear(pResult);

pResult = PQexec(pConn, ToUtf8(strCreate.c_str()).c_str());
if (pResult) PQclear(pResult);

pResult = PQexec(pConn, "select * from test_umlaut");
if (!pResult) FAIL;
if (PQresultStatus(pResult)!=PGRES_TUPLES_OK) FAIL;
if (PQnfields(pResult)!=1) FAIL;
const char *fName = PQfname(pResult,0);

ShowW("Name: ", strName);
ShowA("in UTF8: ", ToUtf8(strName).c_str());
ShowA("from DB: ", fName);
ShowW("in UTF16: ", ToWide(fName).c_str());

PQclear(pResult);
PQreset(pConn);

(ShowA/W call OutputDebugStringA/W, and ToUtf8/ToWide use
WideCharToMultiByte/MultiByteToWideChar with CP_UTF8.)

generates this output:

Name: id_äß
in UTF8: id_äß
from DB: id_ã¤ãÿ
in UTF16: id_???

The back-end treats the name as if it were in ANSI encoding, not in UTF-8,
when it lower-cases the name. The resulting column name is corrupted.

I’m using PostgreSQL 9.2.1, compiled by Visual C++ build 1600, 64-bit

The database uses:
ENCODING = 'UTF8'
LC_COLLATE = 'English_United Kingdom.1252'
LC_CTYPE = 'English_United Kingdom.1252'