diff --git a/handler/ha_innodb.cc b/handler/ha_innodb.cc
index 17e56a94ee2..9270b1b0961 100644
--- a/handler/ha_innodb.cc
+++ b/handler/ha_innodb.cc
@@ -5938,12 +5938,12 @@ ha_innobase::info(
 	}
 
 	if (flag & HA_STATUS_ERRKEY) {
-		dict_index_t* err_index;
+		const dict_index_t*	err_index;
 
 		ut_a(prebuilt->trx);
 		ut_a(prebuilt->trx->magic_n == TRX_MAGIC_N);
 
-		err_index = (dict_index_t*)trx_get_error_info(prebuilt->trx);
+		err_index = trx_get_error_info(prebuilt->trx);
 
 		if (err_index) {
 			errkey = (unsigned int)
diff --git a/include/trx0trx.h b/include/trx0trx.h
index 4c24e47a4a0..3163a7ed39e 100644
--- a/include/trx0trx.h
+++ b/include/trx0trx.h
@@ -79,12 +79,12 @@ trx_set_detailed_error_from_file(
 	FILE*	file);	/* in: file to read message from */
 /********************************************************************
 Retrieves the error_info field from a trx. */
-
-void*
+UNIV_INLINE
+const dict_index_t*
 trx_get_error_info(
 /*===============*/
-			/* out: the error info */
-	trx_t*	trx);	/* in: trx object */
+				/* out: the error info */
+	const trx_t*	trx);	/* in: trx object */
 /********************************************************************
 Creates and initializes a transaction object. */
 
@@ -587,7 +587,7 @@ struct trx_struct{
 					doing the transaction is allowed to
 					set this field: this is NOT protected
 					by the kernel mutex */
-	void*		error_info;	/* if the error number indicates a
+	const dict_index_t*error_info;	/* if the error number indicates a
 					duplicate key error, a pointer to
 					the problematic index is stored here */
 	ulint		error_key_num;	/* if the index creation fails to a
diff --git a/include/trx0trx.ic b/include/trx0trx.ic
index d562db233e9..4463a14764e 100644
--- a/include/trx0trx.ic
+++ b/include/trx0trx.ic
@@ -96,3 +96,15 @@ trx_new_rec_locks_contain(
 	return(trx->new_rec_locks[0] == index
 	       || trx->new_rec_locks[1] == index);
 }
+
+/********************************************************************
+Retrieves the error_info field from a trx. */
+UNIV_INLINE
+const dict_index_t*
+trx_get_error_info(
+/*===============*/
+				/* out: the error info */
+	const trx_t*	trx)	/* in: trx object */
+{
+	return(trx->error_info);
+}
diff --git a/trx/trx0trx.c b/trx/trx0trx.c
index 58bdf7a681e..062fcfe984a 100644
--- a/trx/trx0trx.c
+++ b/trx/trx0trx.c
@@ -60,18 +60,6 @@ trx_set_detailed_error_from_file(
 			    sizeof(trx->detailed_error));
 }
 
-/********************************************************************
-Retrieves the error_info field from a trx. */
-
-void*
-trx_get_error_info(
-/*===============*/
-			/* out: the error info */
-	trx_t*	trx)	/* in: trx object */
-{
-	return(trx->error_info);
-}
-
 /********************************************************************
 Creates and initializes a transaction object. */