Enable unconvert linter

.golangci.yml

@@ -6,6 +6,7 @@ linters:
   enable:
     - govet
     - ineffassign
+    - unconvert
 
 # See: https://golangci-lint.run/usage/formatters/
 formatters:

CLAUDE.md

@@ -69,5 +69,5 @@ Supporting packages:
 - **Context-based** — all blocking operations take `context.Context`.
 - **Tracer interfaces** — observability via `QueryTracer`, `BatchTracer`, `CopyFromTracer`, `PrepareTracer` on `ConnConfig.Tracer`.
 - **Formatting** — always run `goimports -w .` after making changes to ensure code is properly formatted. CI checks formatting via `gofmt -l -s -w . && git diff --exit-code`. `gofumpt` with extra rules is also enforced via `golangci-lint`.
-- **Linters** — `govet` and `ineffassign` only (configured in `.golangci.yml`).
+- **Linters** — `govet`, `ineffassign`, and `unconvert` only (configured in `.golangci.yml`).
 - **CI matrix** — tests run against Go 1.25/1.26 × PostgreSQL 14-18 + CockroachDB, on Linux and Windows. Race detector enabled on Linux only.

conn.go

@@ -833,7 +833,7 @@ optionLoop:
 		if resultFormatsByOID != nil {
 			resultFormats = make([]int16, len(sd.Fields))
 			for i := range resultFormats {
-				resultFormats[i] = resultFormatsByOID[uint32(sd.Fields[i].DataTypeOID)]
+				resultFormats[i] = resultFormatsByOID[sd.Fields[i].DataTypeOID]
 			}
 		}
 

named_args.go

@@ -163,7 +163,7 @@ func namedArgState(l *sqlLexer) stateFn {
 			if _, found := l.nameToOrdinal[na]; !found {
 				l.nameToOrdinal[na] = len(l.nameToOrdinal) + 1
 			}
-			l.parts = append(l.parts, namedArg(na))
+			l.parts = append(l.parts, na)
 			l.start = l.pos
 			return rawState
 		}

pgconn/pgconn.go

@@ -475,7 +475,7 @@ func connectOne(ctx context.Context, config *Config, connectConfig *connectOneCo
 		case *pgproto3.ParameterStatus, *pgproto3.NoticeResponse:
 			// handled by ReceiveMessage
 		case *pgproto3.NegotiateProtocolVersion:
-			serverVersion := pgproto3.ProtocolVersion30&0xFFFF0000 | uint32(msg.NewestMinorProtocol)
+			serverVersion := pgproto3.ProtocolVersion30&0xFFFF0000 | msg.NewestMinorProtocol
 			if serverVersion < minProtocolVersion {
 				pgConn.conn.Close()
 				return nil, newPerDialConnectError("server protocol version too low", nil)
@@ -1008,22 +1008,22 @@ func ErrorResponseToPgError(msg *pgproto3.ErrorResponse) *PgError {
 	return &PgError{
 		Severity:            msg.Severity,
 		SeverityUnlocalized: msg.SeverityUnlocalized,
-		Code:                string(msg.Code),
-		Message:             string(msg.Message),
-		Detail:              string(msg.Detail),
+		Code:                msg.Code,
+		Message:             msg.Message,
+		Detail:              msg.Detail,
 		Hint:                msg.Hint,
 		Position:            msg.Position,
 		InternalPosition:    msg.InternalPosition,
-		InternalQuery:       string(msg.InternalQuery),
-		Where:               string(msg.Where),
-		SchemaName:          string(msg.SchemaName),
-		TableName:           string(msg.TableName),
-		ColumnName:          string(msg.ColumnName),
-		DataTypeName:        string(msg.DataTypeName),
+		InternalQuery:       msg.InternalQuery,
+		Where:               msg.Where,
+		SchemaName:          msg.SchemaName,
+		TableName:           msg.TableName,
+		ColumnName:          msg.ColumnName,
+		DataTypeName:        msg.DataTypeName,
 		ConstraintName:      msg.ConstraintName,
-		File:                string(msg.File),
+		File:                msg.File,
 		Line:                msg.Line,
-		Routine:             string(msg.Routine),
+		Routine:             msg.Routine,
 	}
 }
 

pgconn/pgconn_test.go

@@ -3209,23 +3209,23 @@ func TestPipelinePrepare(t *testing.T) {
 	sd, ok := results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "a", string(sd.Fields[0].Name))
+	require.Equal(t, "a", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.Int8OID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
 	require.NoError(t, err)
 	sd, ok = results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "b", string(sd.Fields[0].Name))
+	require.Equal(t, "b", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.TextOID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
 	require.NoError(t, err)
 	sd, ok = results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "c", string(sd.Fields[0].Name))
+	require.Equal(t, "c", sd.Fields[0].Name)
 	require.Equal(t, []uint32{}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
@@ -3279,7 +3279,7 @@ func TestPipelinePrepareError(t *testing.T) {
 	sd, ok := results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "a", string(sd.Fields[0].Name))
+	require.Equal(t, "a", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.Int8OID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
@@ -3323,7 +3323,7 @@ func TestPipelinePrepareAndDeallocate(t *testing.T) {
 	sd, ok := results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "a", string(sd.Fields[0].Name))
+	require.Equal(t, "a", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.Int8OID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
@@ -3460,7 +3460,7 @@ func TestPipelinePrepareQuery(t *testing.T) {
 	sd, ok := results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "msg", string(sd.Fields[0].Name))
+	require.Equal(t, "msg", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.TextOID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
@@ -3627,7 +3627,7 @@ func TestPipelineFlushForSingleRequests(t *testing.T) {
 	sd, ok := results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "msg", string(sd.Fields[0].Name))
+	require.Equal(t, "msg", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.TextOID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()
@@ -3724,7 +3724,7 @@ func TestPipelineFlushForRequestSeries(t *testing.T) {
 	sd, ok := results.(*pgconn.StatementDescription)
 	require.Truef(t, ok, "expected StatementDescription, got: %#v", results)
 	require.Len(t, sd.Fields, 1)
-	require.Equal(t, "num", string(sd.Fields[0].Name))
+	require.Equal(t, "num", sd.Fields[0].Name)
 	require.Equal(t, []uint32{pgtype.Int8OID}, sd.ParamOIDs)
 
 	results, err = pipeline.GetResults()

pgproto3/close.go

@@ -75,7 +75,7 @@ func (dst *Close) UnmarshalJSON(data []byte) error {
 		return errors.New("invalid length for Close.ObjectType")
 	}
 
-	dst.ObjectType = byte(msg.ObjectType[0])
+	dst.ObjectType = msg.ObjectType[0]
 	dst.Name = msg.Name
 	return nil
 }

pgproto3/describe.go

@@ -74,7 +74,7 @@ func (dst *Describe) UnmarshalJSON(data []byte) error {
 		return errors.New("invalid length for Describe.ObjectType")
 	}
 
-	dst.ObjectType = byte(msg.ObjectType[0])
+	dst.ObjectType = msg.ObjectType[0]
 	dst.Name = msg.Name
 	return nil
 }

pgtype/float4.go

@@ -50,7 +50,7 @@ func (f *Float4) Scan(src any) error {
 		*f = Float4{Float32: float32(src), Valid: true}
 		return nil
 	case string:
-		n, err := strconv.ParseFloat(string(src), 32)
+		n, err := strconv.ParseFloat(src, 32)
 		if err != nil {
 			return err
 		}

pgtype/float8.go

@@ -58,7 +58,7 @@ func (f *Float8) Scan(src any) error {
 		*f = Float8{Float64: src, Valid: true}
 		return nil
 	case string:
-		n, err := strconv.ParseFloat(string(src), 64)
+		n, err := strconv.ParseFloat(src, 64)
 		if err != nil {
 			return err
 		}

pgtype/numeric.go

@@ -132,7 +132,7 @@ func (n *Numeric) ScanScientific(src string) error {
 		return scanPlanTextAnyToNumericScanner{}.Scan([]byte(src), n)
 	}
 
-	if bigF, ok := new(big.Float).SetString(string(src)); ok {
+	if bigF, ok := new(big.Float).SetString(src); ok {
 		smallF, _ := bigF.Float64()
 		src = strconv.FormatFloat(smallF, 'f', -1, 64)
 	}

pgtype/tsvector.go

@@ -174,7 +174,7 @@ func (encodePlanTSVectorCodecBinary) Encode(value any, buf []byte) ([]byte, erro
 
 		// Each position is a uint16: weight (2 bits) | position (14 bits)
 		for _, pos := range entry.Positions {
-			packed := tsvectorWeightToBinary(pos.Weight)<<14 | uint16(pos.Position)&0x3FFF
+			packed := tsvectorWeightToBinary(pos.Weight)<<14 | pos.Position&0x3FFF
 			buf = pgio.AppendUint16(buf, packed)
 		}
 	}

pgtype/uint64.go

@@ -158,7 +158,7 @@ type encodePlanUint64CodecTextUint64 struct{}
 
 func (encodePlanUint64CodecTextUint64) Encode(value any, buf []byte) (newBuf []byte, err error) {
 	v := value.(uint64)
-	return append(buf, strconv.FormatUint(uint64(v), 10)...), nil
+	return append(buf, strconv.FormatUint(v, 10)...), nil
 }
 
 type encodePlanUint64CodecTextUint64Valuer struct{}
@@ -298,7 +298,7 @@ func (scanPlanBinaryUint64ToTextScanner) Scan(src []byte, dst any) error {
 		return fmt.Errorf("invalid length for uint64: %v", len(src))
 	}
 
-	n := uint64(binary.BigEndian.Uint64(src))
+	n := binary.BigEndian.Uint64(src)
 	return s.ScanText(Text{String: strconv.FormatUint(n, 10), Valid: true})
 }
 

rows.go

@@ -554,7 +554,7 @@ func (rs *mapRowScanner) ScanRow(rows Rows) error {
 	*rs = make(mapRowScanner, len(values))
 
 	for i := range values {
-		(*rs)[string(rows.FieldDescriptions()[i].Name)] = values[i]
+		(*rs)[rows.FieldDescriptions()[i].Name] = values[i]
 	}
 
 	return nil

stdlib/sql.go

@@ -641,7 +641,7 @@ func (r *Rows) Columns() []string {
 		fields := r.rows.FieldDescriptions()
 		r.columnNames = make([]string, len(fields))
 		for i, fd := range fields {
-			r.columnNames[i] = string(fd.Name)
+			r.columnNames[i] = fd.Name
 		}
 	}
 

tracer_test.go

@@ -119,13 +119,13 @@ func TestTraceExec(t *testing.T) {
 			require.Equal(t, `select $1::text`, data.SQL)
 			require.Len(t, data.Args, 1)
 			require.Equal(t, `testing`, data.Args[0])
-			return context.WithValue(ctx, ctxKey(ctxKey("fromTraceQueryStart")), "foo")
+			return context.WithValue(ctx, ctxKey("fromTraceQueryStart"), "foo")
 		}
 
 		traceQueryEndCalled := false
 		tracer.traceQueryEnd = func(ctx context.Context, conn *pgx.Conn, data pgx.TraceQueryEndData) {
 			traceQueryEndCalled = true
-			require.Equal(t, "foo", ctx.Value(ctxKey(ctxKey("fromTraceQueryStart"))))
+			require.Equal(t, "foo", ctx.Value(ctxKey("fromTraceQueryStart")))
 			require.Equal(t, `SELECT 1`, data.CommandTag.String())
 			require.NoError(t, data.Err)
 		}