Add casts from jsonb

Add explicit cast from scalar jsonb to all numeric and bool types. It would be
better to have cast from scalar jsonb to text too but there is already a cast
from jsonb to text as just text representation of json. There is no way to have
two different casts for the same type's pair.

Bump catalog version

Author: Anastasia Lubennikova with editorization by Nikita Glukhov and me
Review by: Aleksander Alekseev, Nikita Glukhov, Darafei Praliaskouski
Discussion: https://www.postgresql.org/message-id/flat/0154d35a-24ae-f063-5273-9ffcdf1c7f2e@postgrespro.ru

src/test/regress/expected/jsonb.out

@@ -4191,3 +4191,108 @@ select ts_headline('[]'::jsonb, tsquery('aaa & bbb'));
  []
 (1 row)
 
+-- casts
+select 'true'::jsonb::bool;
+ bool 
+------
+ t
+(1 row)
+
+select '[]'::jsonb::bool;
+ERROR:  jsonb value must be boolean
+select '1.0'::jsonb::float;
+ float8 
+--------
+      1
+(1 row)
+
+select '[1.0]'::jsonb::float;
+ERROR:  jsonb value must be numeric
+select '12345'::jsonb::int4;
+ int4  
+-------
+ 12345
+(1 row)
+
+select '"hello"'::jsonb::int4;
+ERROR:  jsonb value must be numeric
+select '12345'::jsonb::numeric;
+ numeric 
+---------
+   12345
+(1 row)
+
+select '{}'::jsonb::numeric;
+ERROR:  jsonb value must be numeric
+select '12345.05'::jsonb::numeric;
+ numeric  
+----------
+ 12345.05
+(1 row)
+
+select '12345.05'::jsonb::float4;
+ float4 
+--------
+  12345
+(1 row)
+
+select '12345.05'::jsonb::float8;
+  float8  
+----------
+ 12345.05
+(1 row)
+
+select '12345.05'::jsonb::int2;
+ int2  
+-------
+ 12345
+(1 row)
+
+select '12345.05'::jsonb::int4;
+ int4  
+-------
+ 12345
+(1 row)
+
+select '12345.05'::jsonb::int8;
+ int8  
+-------
+ 12345
+(1 row)
+
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::numeric;
+                       numeric                        
+------------------------------------------------------
+ 12345.0000000000000000000000000000000000000000000005
+(1 row)
+
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::float4;
+ float4 
+--------
+  12345
+(1 row)
+
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::float8;
+ float8 
+--------
+  12345
+(1 row)
+
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::int2;
+ int2  
+-------
+ 12345
+(1 row)
+
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::int4;
+ int4  
+-------
+ 12345
+(1 row)
+
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::int8;
+ int8  
+-------
+ 12345
+(1 row)
+

src/test/regress/sql/jsonb.sql

@@ -1105,3 +1105,25 @@ select ts_headline('english', '{"a": "aaa bbb", "b": {"c": "ccc ddd fff", "c1":
 select ts_headline('null'::jsonb, tsquery('aaa & bbb'));
 select ts_headline('{}'::jsonb, tsquery('aaa & bbb'));
 select ts_headline('[]'::jsonb, tsquery('aaa & bbb'));
+
+-- casts
+select 'true'::jsonb::bool;
+select '[]'::jsonb::bool;
+select '1.0'::jsonb::float;
+select '[1.0]'::jsonb::float;
+select '12345'::jsonb::int4;
+select '"hello"'::jsonb::int4;
+select '12345'::jsonb::numeric;
+select '{}'::jsonb::numeric;
+select '12345.05'::jsonb::numeric;
+select '12345.05'::jsonb::float4;
+select '12345.05'::jsonb::float8;
+select '12345.05'::jsonb::int2;
+select '12345.05'::jsonb::int4;
+select '12345.05'::jsonb::int8;
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::numeric;
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::float4;
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::float8;
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::int2;
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::int4;
+select '12345.0000000000000000000000000000000000000000000005'::jsonb::int8;