Arrange for an explicit cast applied to an ARRAY[] constructor to be applied

directly to all the member expressions, instead of the previous implementation
where the ARRAY[] constructor would infer a common element type and then we'd
coerce the finished array after the fact.  This has a number of benefits,
one being that we can allow an empty ARRAY[] construct so long as its
element type is specified by such a cast.

Brendan Jurd, minor fixes by me.

2 files changed, 11 insertions, 0 deletions

diff --git a/src/test/regress/expected/arrays.out b/src/test/regress/expected/arrays.out
index 0f611bf7d78..c82cd3919b9 100644
--- a/src/test/regress/expected/arrays.out
+++ b/src/test/regress/expected/arrays.out
@@ -785,6 +785,9 @@ select '{}}'::text[];
 ERROR:  malformed array literal: "{}}"
 select '{ }}'::text[];
 ERROR:  malformed array literal: "{ }}"
+select array[];
+ERROR:  cannot determine type of empty array
+HINT:  Explicitly cast to the desired type, for example ARRAY[]::integer[].
 -- none of the above should be accepted
 -- all of the following should be accepted
 select '{}'::text[];
@@ -826,6 +829,12 @@ select '{
  {"@ 0","@ 1 hour 42 mins 20 secs"}
 (1 row)
 
+select array[]::text[];
+ array 
+-------
+ {}
+(1 row)
+
 -- all of the above should be accepted
 -- tests for array aggregates
 CREATE TEMP TABLE arraggtest ( f1 INT[], f2 TEXT[][], f3 FLOAT[]);
diff --git a/src/test/regress/sql/arrays.sql b/src/test/regress/sql/arrays.sql
index a60bf560fa8..192648a39b6 100644
--- a/src/test/regress/sql/arrays.sql
+++ b/src/test/regress/sql/arrays.sql
@@ -280,6 +280,7 @@ select E'{{1,2},\\{2,3}}'::text[];
 select '{{"1 2" x},{3}}'::text[];
 select '{}}'::text[];
 select '{ }}'::text[];
+select array[];
 -- none of the above should be accepted
 
 -- all of the following should be accepted
@@ -292,6 +293,7 @@ select '{
            0 second,
            @ 1 hour @ 42 minutes @ 20 seconds
          }'::interval[];
+select array[]::text[];
 -- all of the above should be accepted
 
 -- tests for array aggregates