sql: Some INT and FLOAT alias conversions are illogical

[jseldess]

~/Desktop$ cockroach version
Build Tag:    v1.1.0-rc.1-6-gf3937172b
Build Time:   2017/10/08 20:14:21
Distribution: CCL
Platform:     darwin amd64
Go Version:   go1.9
C Compiler:   4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)
Build SHA-1:  f3937172b903a1884ac9e01a2168de7c41908839
Build Type:   development

Currently, INT8 and INT64 convert to BIGINT, but BIGINT converts to INT:

root@:26257/> create table test.t3 (a int, b integer, c int8, d int64, e bigint, f int2, g smallint);
CREATE TABLE

Time: 7.096365ms

root@:26257/> show create table test.t3;
+---------+----------------------------------------------------+
|  Table  |                    CreateTable                     |
+---------+----------------------------------------------------+
| test.t3 | CREATE TABLE t3 (␤                                 |
|         |     a INT NULL,␤                                   |
|         |     b INTEGER NULL,␤                               |
|         |     c BIGINT NULL,␤                                |
|         |     d BIGINT NULL,␤                                |
|         |     e INT NULL,␤                                   |
|         |     f SMALLINT NULL,␤                              |
|         |     g SMALLINT NULL,␤                              |
|         |     FAMILY "primary" (a, b, c, d, e, f, g, rowid)␤ |
|         | )                                                  |
+---------+----------------------------------------------------+
(1 row)

Also, FLOAT4 converts to DOUBLE PRECISION, but DOUBLE PRECISION converts to FLOAT:

root@:26257/> create table test.floats (a float, b real, c double precision, d float4, e float8);
CREATE TABLE

Time: 6.350415ms

root@:26257/> show create table test.floats;
+-------------+----------------------------------------------+
|    Table    |                 CreateTable                  |
+-------------+----------------------------------------------+
| test.floats | CREATE TABLE floats (␤                       |
|             |     a FLOAT NULL,␤                           |
|             |     b REAL NULL,␤                            |
|             |     c FLOAT NULL,␤                           |
|             |     d REAL NULL,␤                            |
|             |     e DOUBLE PRECISION NULL,␤                |
|             |     FAMILY "primary" (a, b, c, d, e, rowid)␤ |
|             | )                                            |
+-------------+----------------------------------------------+
(1 row)

[jordanlewis]

@m-schneider could you please take a look at this? I think it should be a simple fix, probably.