Remove various unnecessary (char *) casts

Remove a number of (char *) casts that are unnecessary.  Or in some
cases, rewrite the code to make the purpose of the cast clearer.

Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7%40eisentraut.org

src/backend/access/transam/xlog.c

@@ -4287,7 +4287,7 @@ WriteControlFile(void)
 	/* Contents are protected with a CRC */
 	INIT_CRC32C(ControlFile->crc);
 	COMP_CRC32C(ControlFile->crc,
-				(char *) ControlFile,
+				ControlFile,
 				offsetof(ControlFileData, crc));
 	FIN_CRC32C(ControlFile->crc);
 
@@ -4405,7 +4405,7 @@ ReadControlFile(void)
 	/* Now check the CRC. */
 	INIT_CRC32C(crc);
 	COMP_CRC32C(crc,
-				(char *) ControlFile,
+				ControlFile,
 				offsetof(ControlFileData, crc));
 	FIN_CRC32C(crc);
 

src/backend/libpq/auth.c

@@ -2932,8 +2932,8 @@ PerformRadiusTransaction(const char *server, const char *secret, const char *por
 	radius_packet radius_recv_pack;
 	radius_packet *packet = &radius_send_pack;
 	radius_packet *receivepacket = &radius_recv_pack;
-	char	   *radius_buffer = (char *) &radius_send_pack;
-	char	   *receive_buffer = (char *) &radius_recv_pack;
+	void	   *radius_buffer = &radius_send_pack;
+	void	   *receive_buffer = &radius_recv_pack;
 	int32		service = pg_hton32(RADIUS_AUTHENTICATE_ONLY);
 	uint8	   *cryptvector;
 	int			encryptedpasswordlen;
@@ -3204,7 +3204,9 @@ PerformRadiusTransaction(const char *server, const char *secret, const char *por
 																		 * original packet */
 		if (packetlength > RADIUS_HEADER_LENGTH)	/* there may be no
 													 * attributes at all */
-			memcpy(cryptvector + RADIUS_HEADER_LENGTH, receive_buffer + RADIUS_HEADER_LENGTH, packetlength - RADIUS_HEADER_LENGTH);
+			memcpy(cryptvector + RADIUS_HEADER_LENGTH,
+				   (char *) receive_buffer + RADIUS_HEADER_LENGTH,
+				   packetlength - RADIUS_HEADER_LENGTH);
 		memcpy(cryptvector + packetlength, secret, strlen(secret));
 
 		if (!pg_md5_binary(cryptvector,

src/backend/nodes/copyfuncs.c

@@ -40,7 +40,7 @@
 
 /* Copy a field that is a pointer to a C string, or perhaps NULL */
 #define COPY_STRING_FIELD(fldname) \
-	(newnode->fldname = from->fldname ? pstrdup(from->fldname) : (char *) NULL)
+	(newnode->fldname = from->fldname ? pstrdup(from->fldname) : NULL)
 
 /* Copy a field that is an inline array */
 #define COPY_ARRAY_FIELD(fldname) \

src/backend/nodes/makefuncs.c

@@ -51,7 +51,7 @@ makeSimpleA_Expr(A_Expr_Kind kind, char *name,
 	A_Expr	   *a = makeNode(A_Expr);
 
 	a->kind = kind;
-	a->name = list_make1(makeString((char *) name));
+	a->name = list_make1(makeString(name));
 	a->lexpr = lexpr;
 	a->rexpr = rexpr;
 	a->location = location;

src/backend/storage/page/bufpage.c

@@ -1502,7 +1502,7 @@ PageSetChecksumCopy(Page page, BlockNumber blkno)
 
 	/* If we don't need a checksum, just return the passed-in data */
 	if (PageIsNew(page) || !DataChecksumsEnabled())
-		return (char *) page;
+		return page;
 
 	/*
 	 * We allocate the copy space once and use it over on each subsequent

src/backend/utils/cache/relmapper.c

@@ -854,7 +854,7 @@ read_relmap_file(RelMapFile *map, char *dbpath, bool lock_held, int elevel)
 
 	/* verify the CRC */
 	INIT_CRC32C(crc);
-	COMP_CRC32C(crc, (char *) map, offsetof(RelMapFile, crc));
+	COMP_CRC32C(crc, map, offsetof(RelMapFile, crc));
 	FIN_CRC32C(crc);
 
 	if (!EQ_CRC32C(crc, map->crc))
@@ -910,7 +910,7 @@ write_relmap_file(RelMapFile *newmap, bool write_wal, bool send_sinval,
 		elog(ERROR, "attempt to write bogus relation mapping");
 
 	INIT_CRC32C(newmap->crc);
-	COMP_CRC32C(newmap->crc, (char *) newmap, offsetof(RelMapFile, crc));
+	COMP_CRC32C(newmap->crc, newmap, offsetof(RelMapFile, crc));
 	FIN_CRC32C(newmap->crc);
 
 	/*

src/backend/utils/error/jsonlog.c

@@ -206,7 +206,7 @@ write_jsonlog(ErrorData *edata)
 	/* Error severity */
 	if (edata->elevel)
 		appendJSONKeyValue(&buf, "error_severity",
-						   (char *) error_severity(edata->elevel), true);
+						   error_severity(edata->elevel), true);
 
 	/* SQL state code */
 	if (edata->sqlerrcode)