diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 56fed4d87c..a217dbcb1e 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1613,8 +1613,10 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 						errmsg("inherited column \"%s\" has a type conflict",
 							   attributeName),
 							 errdetail("%s versus %s",
-									   TypeNameToString(def->typeName),
-									   format_type_be(attribute->atttypid))));
+									   format_type_with_typemod(defTypeId,
+																deftypmod),
+								format_type_with_typemod(attribute->atttypid,
+													attribute->atttypmod))));
 				defCollId = GetColumnDefCollation(NULL, def, defTypeId);
 				if (defCollId != attribute->attcollation)
 					ereport(ERROR,
@@ -1832,8 +1834,10 @@ MergeAttributes(List *schema, List *supers, char relpersistence,
 							 errmsg("column \"%s\" has a type conflict",
 									attributeName),
 							 errdetail("%s versus %s",
-									   TypeNameToString(def->typeName),
-									   TypeNameToString(newdef->typeName))));
+									   format_type_with_typemod(defTypeId,
+																deftypmod),
+									   format_type_with_typemod(newTypeId,
+																newtypmod))));
 				defcollid = GetColumnDefCollation(NULL, def, defTypeId);
 				newcollid = GetColumnDefCollation(NULL, newdef, newTypeId);
 				if (defcollid != newcollid)
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 228ae6ec22..7c88ddc9fe 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -1268,6 +1268,27 @@ select * from child;
  12 | testing
 (1 row)
 
+drop table child;
+drop table parent;
+-- check error cases for inheritance column merging
+create table parent (a float8, b numeric(10,4), c text collate "C");
+create table child (a float4) inherits (parent); -- fail
+NOTICE:  merging column "a" with inherited definition
+ERROR:  column "a" has a type conflict
+DETAIL:  double precision versus real
+create table child (b decimal(10,7)) inherits (parent); -- fail
+NOTICE:  moving and merging column "b" with inherited definition
+DETAIL:  User-specified column moved to the position of the inherited column.
+ERROR:  column "b" has a type conflict
+DETAIL:  numeric(10,4) versus numeric(10,7)
+create table child (c text collate "POSIX") inherits (parent); -- fail
+NOTICE:  moving and merging column "c" with inherited definition
+DETAIL:  User-specified column moved to the position of the inherited column.
+ERROR:  column "c" has a collation conflict
+DETAIL:  "C" versus "POSIX"
+create table child (a double precision, b decimal(10,4)) inherits (parent);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging column "b" with inherited definition
 drop table child;
 drop table parent;
 -- test copy in/out
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 3db3460973..72e65d4ee0 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -906,6 +906,17 @@ select * from child;
 drop table child;
 drop table parent;
 
+-- check error cases for inheritance column merging
+create table parent (a float8, b numeric(10,4), c text collate "C");
+
+create table child (a float4) inherits (parent); -- fail
+create table child (b decimal(10,7)) inherits (parent); -- fail
+create table child (c text collate "POSIX") inherits (parent); -- fail
+create table child (a double precision, b decimal(10,4)) inherits (parent);
+
+drop table child;
+drop table parent;
+
 -- test copy in/out
 create table test (a int4, b int4, c int4);
 insert into test values (1,2,3);