Merge "propose emulated setinputsizes embedded in the compiler" into main

15 files changed, 296 insertions, 268 deletions

diff --git a/lib/sqlalchemy/connectors/pyodbc.py b/lib/sqlalchemy/connectors/pyodbc.py
index 3aff7b479..4d684acbb 100644
--- a/lib/sqlalchemy/connectors/pyodbc.py
+++ b/lib/sqlalchemy/connectors/pyodbc.py
@@ -10,6 +10,7 @@ from urllib.parse import unquote_plus
 
 from . import Connector
 from .. import util
+from ..engine import interfaces
 
 
 class PyODBCConnector(Connector):
@@ -22,15 +23,14 @@ class PyODBCConnector(Connector):
     supports_native_decimal = True
     default_paramstyle = "named"
 
-    use_setinputsizes = False
-
     # for non-DSN connections, this *may* be used to
     # hold the desired driver name
     pyodbc_driver_name = None
 
     def __init__(self, use_setinputsizes=False, **kw):
         super(PyODBCConnector, self).__init__(**kw)
-        self.use_setinputsizes = use_setinputsizes
+        if use_setinputsizes:
+            self.bind_typing = interfaces.BindTyping.SETINPUTSIZES
 
     @classmethod
     def dbapi(cls):
@@ -161,8 +161,9 @@ class PyODBCConnector(Connector):
         # for types such as pyodbc.SQL_WLONGVARCHAR, which is the datatype
         # that ticket #5649 is targeting.
 
-        # NOTE: as of #6058, this won't be called if the use_setinputsizes flag
-        # is False, or if no types were specified in list_of_tuples
+        # NOTE: as of #6058, this won't be called if the use_setinputsizes
+        # parameter were not passed to the dialect, or if no types were
+        # specified in list_of_tuples
 
         cursor.setinputsizes(
             [
diff --git a/lib/sqlalchemy/dialects/oracle/cx_oracle.py b/lib/sqlalchemy/dialects/oracle/cx_oracle.py
index 07317126d..a1d093886 100644
--- a/lib/sqlalchemy/dialects/oracle/cx_oracle.py
+++ b/lib/sqlalchemy/dialects/oracle/cx_oracle.py
@@ -443,6 +443,7 @@ from ... import processors
 from ... import types as sqltypes
 from ... import util
 from ...engine import cursor as _cursor
+from ...engine import interfaces
 
 
 class _OracleInteger(sqltypes.Integer):
@@ -780,8 +781,6 @@ class OracleExecutionContext_cx_oracle(OracleExecutionContext):
 
         self._generate_cursor_outputtype_handler()
 
-        self.include_set_input_sizes = self.dialect._include_setinputsizes
-
     def post_exec(self):
         if self.compiled and self.out_parameters and self.compiled.returning:
             # create a fake cursor result from the out parameters. unlike
@@ -830,7 +829,7 @@ class OracleDialect_cx_oracle(OracleDialect):
     supports_sane_rowcount = True
     supports_sane_multi_rowcount = True
 
-    use_setinputsizes = True
+    bind_typing = interfaces.BindTyping.SETINPUTSIZES
 
     driver = "cx_oracle"
 
@@ -906,7 +905,6 @@ class OracleDialect_cx_oracle(OracleDialect):
         cx_Oracle = self.dbapi
 
         if cx_Oracle is None:
-            self._include_setinputsizes = {}
             self.cx_oracle_ver = (0, 0, 0)
         else:
             self.cx_oracle_ver = self._parse_cx_oracle_ver(cx_Oracle.version)
@@ -922,7 +920,7 @@ class OracleDialect_cx_oracle(OracleDialect):
                 )
                 self._cursor_var_unicode_kwargs = util.immutabledict()
 
-            self._include_setinputsizes = {
+            self.include_set_input_sizes = {
                 cx_Oracle.DATETIME,
                 cx_Oracle.NCLOB,
                 cx_Oracle.CLOB,
@@ -932,9 +930,9 @@ class OracleDialect_cx_oracle(OracleDialect):
                 cx_Oracle.BLOB,
                 cx_Oracle.FIXED_CHAR,
                 cx_Oracle.TIMESTAMP,
-                _OracleInteger,
-                _OracleBINARY_FLOAT,
-                _OracleBINARY_DOUBLE,
+                int,  # _OracleInteger,
+                # _OracleBINARY_FLOAT, _OracleBINARY_DOUBLE,
+                cx_Oracle.NATIVE_FLOAT,
             }
 
             self._paramval = lambda value: value.getvalue()
diff --git a/lib/sqlalchemy/dialects/postgresql/array.py b/lib/sqlalchemy/dialects/postgresql/array.py
index 614559035..ebe47c8d1 100644
--- a/lib/sqlalchemy/dialects/postgresql/array.py
+++ b/lib/sqlalchemy/dialects/postgresql/array.py
@@ -330,9 +330,6 @@ class ARRAY(sqltypes.ARRAY):
             and self.item_type.native_enum
         )
 
-    def bind_expression(self, bindvalue):
-        return bindvalue
-
     def bind_processor(self, dialect):
         item_proc = self.item_type.dialect_impl(dialect).bind_processor(
             dialect
diff --git a/lib/sqlalchemy/dialects/postgresql/asyncpg.py b/lib/sqlalchemy/dialects/postgresql/asyncpg.py
index d6cde0087..5ef9df800 100644
--- a/lib/sqlalchemy/dialects/postgresql/asyncpg.py
+++ b/lib/sqlalchemy/dialects/postgresql/asyncpg.py
@@ -135,32 +135,28 @@ except ImportError:
     _python_UUID = None
 
 
+class AsyncpgString(sqltypes.String):
+    render_bind_cast = True
+
+
 class AsyncpgTime(sqltypes.Time):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.TIME
+    render_bind_cast = True
 
 
 class AsyncpgDate(sqltypes.Date):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.DATE
+    render_bind_cast = True
 
 
 class AsyncpgDateTime(sqltypes.DateTime):
-    def get_dbapi_type(self, dbapi):
-        if self.timezone:
-            return dbapi.TIMESTAMP_W_TZ
-        else:
-            return dbapi.TIMESTAMP
+    render_bind_cast = True
 
 
 class AsyncpgBoolean(sqltypes.Boolean):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.BOOLEAN
+    render_bind_cast = True
 
 
 class AsyncPgInterval(INTERVAL):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTERVAL
+    render_bind_cast = True
 
     @classmethod
     def adapt_emulated_to_native(cls, interval, **kw):
@@ -169,49 +165,45 @@ class AsyncPgInterval(INTERVAL):
 
 
 class AsyncPgEnum(ENUM):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.ENUM
+    render_bind_cast = True
 
 
 class AsyncpgInteger(sqltypes.Integer):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTEGER
+    render_bind_cast = True
 
 
 class AsyncpgBigInteger(sqltypes.BigInteger):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.BIGINTEGER
+    render_bind_cast = True
 
 
 class AsyncpgJSON(json.JSON):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.JSON
+    render_bind_cast = True
 
     def result_processor(self, dialect, coltype):
         return None
 
 
 class AsyncpgJSONB(json.JSONB):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.JSONB
+    render_bind_cast = True
 
     def result_processor(self, dialect, coltype):
         return None
 
 
 class AsyncpgJSONIndexType(sqltypes.JSON.JSONIndexType):
-    def get_dbapi_type(self, dbapi):
-        raise NotImplementedError("should not be here")
+    pass
 
 
 class AsyncpgJSONIntIndexType(sqltypes.JSON.JSONIntIndexType):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTEGER
+    __visit_name__ = "json_int_index"
+
+    render_bind_cast = True
 
 
 class AsyncpgJSONStrIndexType(sqltypes.JSON.JSONStrIndexType):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.STRING
+    __visit_name__ = "json_str_index"
+
+    render_bind_cast = True
 
 
 class AsyncpgJSONPathType(json.JSONPathType):
@@ -225,8 +217,7 @@ class AsyncpgJSONPathType(json.JSONPathType):
 
 
 class AsyncpgUUID(UUID):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.UUID
+    render_bind_cast = True
 
     def bind_processor(self, dialect):
         if not self.as_uuid and dialect.use_native_uuid:
@@ -250,8 +241,7 @@ class AsyncpgUUID(UUID):
 
 
 class AsyncpgNumeric(sqltypes.Numeric):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.NUMBER
+    render_bind_cast = True
 
     def bind_processor(self, dialect):
         return None
@@ -282,18 +272,16 @@ class AsyncpgNumeric(sqltypes.Numeric):
 
 
 class AsyncpgFloat(AsyncpgNumeric):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.FLOAT
+    __visit_name__ = "float"
+    render_bind_cast = True
 
 
 class AsyncpgREGCLASS(REGCLASS):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.STRING
+    render_bind_cast = True
 
 
 class AsyncpgOID(OID):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTEGER
+    render_bind_cast = True
 
 
 class PGExecutionContext_asyncpg(PGExecutionContext):
@@ -318,11 +306,6 @@ class PGExecutionContext_asyncpg(PGExecutionContext):
         if not self.compiled:
             return
 
-        # we have to exclude ENUM because "enum" not really a "type"
-        # we can cast to, it has to be the name of the type itself.
-        # for now we just omit it from casting
-        self.exclude_set_input_sizes = {AsyncAdapt_asyncpg_dbapi.ENUM}
-
     def create_server_side_cursor(self):
         return self._dbapi_connection.cursor(server_side=True)
 
@@ -368,15 +351,7 @@ class AsyncAdapt_asyncpg_cursor:
         self._adapt_connection._handle_exception(error)
 
     def _parameter_placeholders(self, params):
-        if not self._inputsizes:
-            return tuple("$%d" % idx for idx, _ in enumerate(params, 1))
-        else:
-            return tuple(
-                "$%d::%s" % (idx, typ) if typ else "$%d" % idx
-                for idx, typ in enumerate(
-                    (_pg_types.get(typ) for typ in self._inputsizes), 1
-                )
-            )
+        return tuple(f"${idx:d}" for idx, _ in enumerate(params, 1))
 
     async def _prepare_and_execute(self, operation, parameters):
         adapt_connection = self._adapt_connection
@@ -465,7 +440,7 @@ class AsyncAdapt_asyncpg_cursor:
         )
 
     def setinputsizes(self, *inputsizes):
-        self._inputsizes = inputsizes
+        raise NotImplementedError()
 
     def __iter__(self):
         while self._rows:
@@ -799,6 +774,12 @@ class AsyncAdapt_asyncpg_dbapi:
                 "all prepared caches in response to this exception)",
             )
 
+    # pep-249 datatype placeholders.  As of SQLAlchemy 2.0 these aren't
+    # used, however the test suite looks for these in a few cases.
+    STRING = util.symbol("STRING")
+    NUMBER = util.symbol("NUMBER")
+    DATETIME = util.symbol("DATETIME")
+
     @util.memoized_property
     def _asyncpg_error_translate(self):
         import asyncpg
@@ -815,50 +796,6 @@ class AsyncAdapt_asyncpg_dbapi:
     def Binary(self, value):
         return value
 
-    STRING = util.symbol("STRING")
-    TIMESTAMP = util.symbol("TIMESTAMP")
-    TIMESTAMP_W_TZ = util.symbol("TIMESTAMP_W_TZ")
-    TIME = util.symbol("TIME")
-    DATE = util.symbol("DATE")
-    INTERVAL = util.symbol("INTERVAL")
-    NUMBER = util.symbol("NUMBER")
-    FLOAT = util.symbol("FLOAT")
-    BOOLEAN = util.symbol("BOOLEAN")
-    INTEGER = util.symbol("INTEGER")
-    BIGINTEGER = util.symbol("BIGINTEGER")
-    BYTES = util.symbol("BYTES")
-    DECIMAL = util.symbol("DECIMAL")
-    JSON = util.symbol("JSON")
-    JSONB = util.symbol("JSONB")
-    ENUM = util.symbol("ENUM")
-    UUID = util.symbol("UUID")
-    BYTEA = util.symbol("BYTEA")
-
-    DATETIME = TIMESTAMP
-    BINARY = BYTEA
-
-
-_pg_types = {
-    AsyncAdapt_asyncpg_dbapi.STRING: "varchar",
-    AsyncAdapt_asyncpg_dbapi.TIMESTAMP: "timestamp",
-    AsyncAdapt_asyncpg_dbapi.TIMESTAMP_W_TZ: "timestamp with time zone",
-    AsyncAdapt_asyncpg_dbapi.DATE: "date",
-    AsyncAdapt_asyncpg_dbapi.TIME: "time",
-    AsyncAdapt_asyncpg_dbapi.INTERVAL: "interval",
-    AsyncAdapt_asyncpg_dbapi.NUMBER: "numeric",
-    AsyncAdapt_asyncpg_dbapi.FLOAT: "float",
-    AsyncAdapt_asyncpg_dbapi.BOOLEAN: "bool",
-    AsyncAdapt_asyncpg_dbapi.INTEGER: "integer",
-    AsyncAdapt_asyncpg_dbapi.BIGINTEGER: "bigint",
-    AsyncAdapt_asyncpg_dbapi.BYTES: "bytes",
-    AsyncAdapt_asyncpg_dbapi.DECIMAL: "decimal",
-    AsyncAdapt_asyncpg_dbapi.JSON: "json",
-    AsyncAdapt_asyncpg_dbapi.JSONB: "jsonb",
-    AsyncAdapt_asyncpg_dbapi.ENUM: "enum",
-    AsyncAdapt_asyncpg_dbapi.UUID: "uuid",
-    AsyncAdapt_asyncpg_dbapi.BYTEA: "bytea",
-}
-
 
 class PGDialect_asyncpg(PGDialect):
     driver = "asyncpg"
@@ -866,19 +803,20 @@ class PGDialect_asyncpg(PGDialect):
 
     supports_server_side_cursors = True
 
+    render_bind_cast = True
+
     default_paramstyle = "format"
     supports_sane_multi_rowcount = False
     execution_ctx_cls = PGExecutionContext_asyncpg
     statement_compiler = PGCompiler_asyncpg
     preparer = PGIdentifierPreparer_asyncpg
 
-    use_setinputsizes = True
-
     use_native_uuid = True
 
     colspecs = util.update_copy(
         PGDialect.colspecs,
         {
+            sqltypes.String: AsyncpgString,
             sqltypes.Time: AsyncpgTime,
             sqltypes.Date: AsyncpgDate,
             sqltypes.DateTime: AsyncpgDateTime,
@@ -978,20 +916,6 @@ class PGDialect_asyncpg(PGDialect):
                 e, self.dbapi.InterfaceError
             ) and "connection is closed" in str(e)
 
-    def do_set_input_sizes(self, cursor, list_of_tuples, context):
-        if self.positional:
-            cursor.setinputsizes(
-                *[dbtype for key, dbtype, sqltype in list_of_tuples]
-            )
-        else:
-            cursor.setinputsizes(
-                **{
-                    key: dbtype
-                    for key, dbtype, sqltype in list_of_tuples
-                    if dbtype
-                }
-            )
-
     async def setup_asyncpg_json_codec(self, conn):
         """set up JSON codec for asyncpg.
 
diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index d00318fc8..008398865 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -1388,6 +1388,7 @@ from ... import sql
 from ... import util
 from ...engine import characteristics
 from ...engine import default
+from ...engine import interfaces
 from ...engine import reflection
 from ...sql import coercions
 from ...sql import compiler
@@ -2041,16 +2042,6 @@ class ENUM(sqltypes.NativeForEmulated, sqltypes.Enum):
             self.drop(bind=bind, checkfirst=checkfirst)
 
 
-class _ColonCast(elements.CompilerColumnElement):
-    __visit_name__ = "colon_cast"
-    __slots__ = ("type", "clause", "typeclause")
-
-    def __init__(self, expression, type_):
-        self.type = type_
-        self.clause = expression
-        self.typeclause = elements.TypeClause(type_)
-
-
 colspecs = {
     sqltypes.ARRAY: _array.ARRAY,
     sqltypes.Interval: INTERVAL,
@@ -2106,11 +2097,12 @@ ischema_names = {
 
 
 class PGCompiler(compiler.SQLCompiler):
-    def visit_colon_cast(self, element, **kw):
-        return "%s::%s" % (
-            element.clause._compiler_dispatch(self, **kw),
-            element.typeclause._compiler_dispatch(self, **kw),
-        )
+    def render_bind_cast(self, type_, dbapi_type, sqltext):
+        return f"""{sqltext}::{
+                self.dialect.type_compiler.process(
+                    dbapi_type, identifier_preparer=self.preparer
+                )
+            }"""
 
     def visit_array(self, element, **kw):
         return "ARRAY[%s]" % self.visit_clauselist(element, **kw)
@@ -2852,6 +2844,12 @@ class PGTypeCompiler(compiler.GenericTypeCompiler):
     def visit_TSTZRANGE(self, type_, **kw):
         return "TSTZRANGE"
 
+    def visit_json_int_index(self, type_, **kw):
+        return "INT"
+
+    def visit_json_str_index(self, type_, **kw):
+        return "TEXT"
+
     def visit_datetime(self, type_, **kw):
         return self.visit_TIMESTAMP(type_, **kw)
 
@@ -3119,6 +3117,8 @@ class PGDialect(default.DefaultDialect):
     max_identifier_length = 63
     supports_sane_rowcount = True
 
+    bind_typing = interfaces.BindTyping.RENDER_CASTS
+
     supports_native_enum = True
     supports_native_boolean = True
     supports_smallserial = True
diff --git a/lib/sqlalchemy/dialects/postgresql/pg8000.py b/lib/sqlalchemy/dialects/postgresql/pg8000.py
index ac29b28e9..ede953195 100644
--- a/lib/sqlalchemy/dialects/postgresql/pg8000.py
+++ b/lib/sqlalchemy/dialects/postgresql/pg8000.py
@@ -94,7 +94,6 @@ import re
 from uuid import UUID as _python_UUID
 
 from .array import ARRAY as PGARRAY
-from .base import _ColonCast
 from .base import _DECIMAL_TYPES
 from .base import _FLOAT_TYPES
 from .base import _INT_TYPES
@@ -115,7 +114,13 @@ from ... import util
 from ...sql.elements import quoted_name
 
 
+class _PGString(sqltypes.String):
+    render_bind_cast = True
+
+
 class _PGNumeric(sqltypes.Numeric):
+    render_bind_cast = True
+
     def result_processor(self, dialect, coltype):
         if self.asdecimal:
             if coltype in _FLOAT_TYPES:
@@ -141,26 +146,29 @@ class _PGNumeric(sqltypes.Numeric):
                 )
 
 
+class _PGFloat(_PGNumeric):
+    __visit_name__ = "float"
+    render_bind_cast = True
+
+
 class _PGNumericNoBind(_PGNumeric):
     def bind_processor(self, dialect):
         return None
 
 
 class _PGJSON(JSON):
+    render_bind_cast = True
+
     def result_processor(self, dialect, coltype):
         return None
 
-    def get_dbapi_type(self, dbapi):
-        return dbapi.JSON
-
 
 class _PGJSONB(JSONB):
+    render_bind_cast = True
+
     def result_processor(self, dialect, coltype):
         return None
 
-    def get_dbapi_type(self, dbapi):
-        return dbapi.JSONB
-
 
 class _PGJSONIndexType(sqltypes.JSON.JSONIndexType):
     def get_dbapi_type(self, dbapi):
@@ -168,21 +176,26 @@ class _PGJSONIndexType(sqltypes.JSON.JSONIndexType):
 
 
 class _PGJSONIntIndexType(sqltypes.JSON.JSONIntIndexType):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTEGER
+    __visit_name__ = "json_int_index"
+
+    render_bind_cast = True
 
 
 class _PGJSONStrIndexType(sqltypes.JSON.JSONStrIndexType):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.STRING
+    __visit_name__ = "json_str_index"
+
+    render_bind_cast = True
 
 
 class _PGJSONPathType(JSONPathType):
-    def get_dbapi_type(self, dbapi):
-        return 1009
+    pass
+
+    # DBAPI type 1009
 
 
 class _PGUUID(UUID):
+    render_bind_cast = True
+
     def bind_processor(self, dialect):
         if not self.as_uuid:
 
@@ -210,6 +223,8 @@ class _PGEnum(ENUM):
 
 
 class _PGInterval(INTERVAL):
+    render_bind_cast = True
+
     def get_dbapi_type(self, dbapi):
         return dbapi.INTERVAL
 
@@ -219,48 +234,39 @@ class _PGInterval(INTERVAL):
 
 
 class _PGTimeStamp(sqltypes.DateTime):
-    def get_dbapi_type(self, dbapi):
-        if self.timezone:
-            # TIMESTAMPTZOID
-            return 1184
-        else:
-            # TIMESTAMPOID
-            return 1114
+    render_bind_cast = True
+
+
+class _PGDate(sqltypes.Date):
+    render_bind_cast = True
 
 
 class _PGTime(sqltypes.Time):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.TIME
+    render_bind_cast = True
 
 
 class _PGInteger(sqltypes.Integer):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTEGER
+    render_bind_cast = True
 
 
 class _PGSmallInteger(sqltypes.SmallInteger):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.INTEGER
+    render_bind_cast = True
 
 
 class _PGNullType(sqltypes.NullType):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.NULLTYPE
+    pass
 
 
 class _PGBigInteger(sqltypes.BigInteger):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.BIGINTEGER
+    render_bind_cast = True
 
 
 class _PGBoolean(sqltypes.Boolean):
-    def get_dbapi_type(self, dbapi):
-        return dbapi.BOOLEAN
+    render_bind_cast = True
 
 
 class _PGARRAY(PGARRAY):
-    def bind_expression(self, bindvalue):
-        return _ColonCast(bindvalue, self)
+    render_bind_cast = True
 
 
 _server_side_id = util.counter()
@@ -362,7 +368,7 @@ class PGDialect_pg8000(PGDialect):
     preparer = PGIdentifierPreparer_pg8000
     supports_server_side_cursors = True
 
-    use_setinputsizes = True
+    render_bind_cast = True
 
     # reversed as of pg8000 1.16.6.  1.16.5 and lower
     # are no longer compatible
@@ -372,8 +378,9 @@ class PGDialect_pg8000(PGDialect):
     colspecs = util.update_copy(
         PGDialect.colspecs,
         {
+            sqltypes.String: _PGString,
             sqltypes.Numeric: _PGNumericNoBind,
-            sqltypes.Float: _PGNumeric,
+            sqltypes.Float: _PGFloat,
             sqltypes.JSON: _PGJSON,
             sqltypes.Boolean: _PGBoolean,
             sqltypes.NullType: _PGNullType,
@@ -386,6 +393,8 @@ class PGDialect_pg8000(PGDialect):
             sqltypes.Interval: _PGInterval,
             INTERVAL: _PGInterval,
             sqltypes.DateTime: _PGTimeStamp,
+            sqltypes.DateTime: _PGTimeStamp,
+            sqltypes.Date: _PGDate,
             sqltypes.Time: _PGTime,
             sqltypes.Integer: _PGInteger,
             sqltypes.SmallInteger: _PGSmallInteger,
@@ -517,20 +526,6 @@ class PGDialect_pg8000(PGDialect):
         cursor.execute("COMMIT")
         cursor.close()
 
-    def do_set_input_sizes(self, cursor, list_of_tuples, context):
-        if self.positional:
-            cursor.setinputsizes(
-                *[dbtype for key, dbtype, sqltype in list_of_tuples]
-            )
-        else:
-            cursor.setinputsizes(
-                **{
-                    key: dbtype
-                    for key, dbtype, sqltype in list_of_tuples
-                    if dbtype
-                }
-            )
-
     def do_begin_twophase(self, connection, xid):
         connection.connection.tpc_begin((0, xid, ""))
 
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index 11a5f31a3..39b6e0ed1 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -448,7 +448,6 @@ import re
 from uuid import UUID as _python_UUID
 
 from .array import ARRAY as PGARRAY
-from .base import _ColonCast
 from .base import _DECIMAL_TYPES
 from .base import _FLOAT_TYPES
 from .base import _INT_TYPES
@@ -514,8 +513,7 @@ class _PGHStore(HSTORE):
 
 
 class _PGARRAY(PGARRAY):
-    def bind_expression(self, bindvalue):
-        return _ColonCast(bindvalue, self)
+    render_bind_cast = True
 
 
 class _PGJSON(JSON):
diff --git a/lib/sqlalchemy/engine/__init__.py b/lib/sqlalchemy/engine/__init__.py
index ba57eee51..5f4c5be47 100644
--- a/lib/sqlalchemy/engine/__init__.py
+++ b/lib/sqlalchemy/engine/__init__.py
@@ -33,6 +33,7 @@ from .cursor import CursorResult
 from .cursor import FullyBufferedResultProxy
 from .cursor import ResultProxy
 from .interfaces import AdaptedConnection
+from .interfaces import BindTyping
 from .interfaces import Compiled
 from .interfaces import Connectable
 from .interfaces import CreateEnginePlugin
diff --git a/lib/sqlalchemy/engine/base.py b/lib/sqlalchemy/engine/base.py
index d2939c035..bfadcbce6 100644
--- a/lib/sqlalchemy/engine/base.py
+++ b/lib/sqlalchemy/engine/base.py
@@ -7,6 +7,7 @@
 import contextlib
 import sys
 
+from .interfaces import BindTyping
 from .interfaces import Connectable
 from .interfaces import ConnectionEventsTarget
 from .interfaces import ExceptionContext
@@ -1484,7 +1485,7 @@ class Connection(Connectable):
 
         context.pre_exec()
 
-        if dialect.use_setinputsizes:
+        if dialect.bind_typing is BindTyping.SETINPUTSIZES:
             context._set_input_sizes()
 
         cursor, statement, parameters = (
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index a47ed963d..cb04eb525 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -53,9 +53,13 @@ class DefaultDialect(interfaces.Dialect):
     supports_alter = True
     supports_comments = False
     inline_comments = False
-    use_setinputsizes = False
     supports_statement_cache = True
 
+    bind_typing = interfaces.BindTyping.NONE
+
+    include_set_input_sizes = None
+    exclude_set_input_sizes = None
+
     # the first value we'd get for an autoincrement
     # column.
     default_sequence_base = 1
@@ -261,6 +265,15 @@ class DefaultDialect(interfaces.Dialect):
             else:
                 self.server_side_cursors = True
 
+        if getattr(self, "use_setinputsizes", False):
+            util.warn_deprecated(
+                "The dialect-level use_setinputsizes attribute is "
+                "deprecated.  Please use "
+                "bind_typing = BindTyping.SETINPUTSIZES",
+                "2.0",
+            )
+            self.bind_typing = interfaces.BindTyping.SETINPUTSIZES
+
         self.encoding = encoding
         self.positional = False
         self._ischema = None
@@ -288,6 +301,10 @@ class DefaultDialect(interfaces.Dialect):
         self.label_length = label_length
         self.compiler_linting = compiler_linting
 
+    @util.memoized_property
+    def _bind_typing_render_casts(self):
+        return self.bind_typing is interfaces.BindTyping.RENDER_CASTS
+
     def _ensure_has_table_connection(self, arg):
 
         if not isinstance(arg, Connection):
@@ -737,9 +754,6 @@ class DefaultExecutionContext(interfaces.ExecutionContext):
     returned_default_rows = None
     execution_options = util.immutabledict()
 
-    include_set_input_sizes = None
-    exclude_set_input_sizes = None
-
     cursor_fetch_strategy = _cursor._DEFAULT_FETCH
 
     cache_stats = None
@@ -1374,8 +1388,14 @@ class DefaultExecutionContext(interfaces.ExecutionContext):
         style of ``setinputsizes()`` on the cursor, using DB-API types
         from the bind parameter's ``TypeEngine`` objects.
 
-        This method only called by those dialects which require it,
-        currently cx_oracle, asyncpg and pg8000.
+        This method only called by those dialects which set
+        the :attr:`.Dialect.bind_typing` attribute to
+        :attr:`.BindTyping.SETINPUTSIZES`.   cx_Oracle is the only DBAPI
+        that requires setinputsizes(), pyodbc offers it as an option.
+
+        Prior to SQLAlchemy 2.0, the setinputsizes() approach was also used
+        for pg8000 and asyncpg, which has been changed to inline rendering
+        of casts.
 
         """
         if self.isddl or self.is_text:
@@ -1383,10 +1403,7 @@ class DefaultExecutionContext(interfaces.ExecutionContext):
 
         compiled = self.compiled
 
-        inputsizes = compiled._get_set_input_sizes_lookup(
-            include_types=self.include_set_input_sizes,
-            exclude_types=self.exclude_set_input_sizes,
-        )
+        inputsizes = compiled._get_set_input_sizes_lookup()
 
         if inputsizes is None:
             return
diff --git a/lib/sqlalchemy/engine/interfaces.py b/lib/sqlalchemy/engine/interfaces.py
index 6772a27bd..251d01c5e 100644
--- a/lib/sqlalchemy/engine/interfaces.py
+++ b/lib/sqlalchemy/engine/interfaces.py
@@ -7,10 +7,60 @@
 
 """Define core interfaces used by the engine system."""
 
+from enum import Enum
+
 from ..sql.compiler import Compiled  # noqa
 from ..sql.compiler import TypeCompiler  # noqa
 
 
+class BindTyping(Enum):
+    """Define different methods of passing typing information for
+    bound parameters in a statement to the database driver.
+
+    .. versionadded:: 2.0
+
+    """
+
+    NONE = 1
+    """No steps are taken to pass typing information to the database driver.
+
+    This is the default behavior for databases such as SQLite, MySQL / MariaDB,
+    SQL Server.
+
+    """
+
+    SETINPUTSIZES = 2
+    """Use the pep-249 setinputsizes method.
+
+    This is only implemented for DBAPIs that support this method and for which
+    the SQLAlchemy dialect has the appropriate infrastructure for that
+    dialect set up.   Current dialects include cx_Oracle as well as
+    optional support for SQL Server using pyodbc.
+
+    When using setinputsizes, dialects also have a means of only using the
+    method for certain datatypes using include/exclude lists.
+
+    When SETINPUTSIZES is used, the :meth:`.Dialect.do_set_input_sizes` method
+    is called for each statement executed which has bound parameters.
+
+    """
+
+    RENDER_CASTS = 3
+    """Render casts or other directives in the SQL string.
+
+    This method is used for all PostgreSQL dialects, including asyncpg,
+    pg8000, psycopg, psycopg2.   Dialects which implement this can choose
+    which kinds of datatypes are explicitly cast in SQL statements and which
+    aren't.
+
+    When RENDER_CASTS is used, the compiler will invoke the
+    :meth:`.SQLCompiler.render_bind_cast` method for each
+    :class:`.BindParameter` object whose dialect-level type sets the
+    :attr:`.TypeEngine.render_bind_cast` attribute.
+
+    """
+
+
 class Dialect:
     """Define the behavior of a specific database and DB-API combination.
 
@@ -156,6 +206,16 @@ class Dialect:
 
     """
 
+    bind_typing = BindTyping.NONE
+    """define a means of passing typing information to the database and/or
+    driver for bound parameters.
+
+    See :class:`.BindTyping` for values.
+
+    ..versionadded:: 2.0
+
+    """
+
     def create_connect_args(self, url):
         """Build DB-API compatible connection arguments.
 
@@ -587,7 +647,9 @@ class Dialect:
     def do_set_input_sizes(self, cursor, list_of_tuples, context):
         """invoke the cursor.setinputsizes() method with appropriate arguments
 
-        This hook is called if the dialect.use_inputsizes flag is set to True.
+        This hook is called if the :attr:`.Dialect.bind_typing` attribute is
+        set to the
+        :attr:`.BindTyping.SETINPUTSIZES` value.
         Parameter data is passed in a list of tuples (paramname, dbtype,
         sqltype), where ``paramname`` is the key of the parameter in the
         statement, ``dbtype`` is the DBAPI datatype and ``sqltype`` is the
@@ -595,6 +657,12 @@ class Dialect:
 
         .. versionadded:: 1.4
 
+        .. versionchanged:: 2.0  - setinputsizes mode is now enabled by
+           setting :attr:`.Dialect.bind_typing` to
+           :attr:`.BindTyping.SETINPUTSIZES`.  Dialects which accept
+           a ``use_setinputsizes`` parameter should set this value
+           appropriately.
+
 
         """
         raise NotImplementedError()
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 0dd61d675..28c1bf069 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -228,6 +228,7 @@ FUNCTIONS = {
     functions.grouping_sets: "GROUPING SETS",
 }
 
+
 EXTRACT_MAP = {
     "month": "month",
     "day": "day",
@@ -1037,57 +1038,28 @@ class SQLCompiler(Compiled):
             return pd
 
     @util.memoized_instancemethod
-    def _get_set_input_sizes_lookup(
-        self, include_types=None, exclude_types=None
-    ):
-        if not hasattr(self, "bind_names"):
-            return None
-
+    def _get_set_input_sizes_lookup(self):
         dialect = self.dialect
-        dbapi = self.dialect.dbapi
 
-        # _unwrapped_dialect_impl() is necessary so that we get the
-        # correct dialect type for a custom TypeDecorator, or a Variant,
-        # which is also a TypeDecorator.   Special types like Interval,
-        # that use TypeDecorator but also might be mapped directly
-        # for a dialect impl, also subclass Emulated first which overrides
-        # this behavior in those cases to behave like the default.
+        include_types = dialect.include_set_input_sizes
+        exclude_types = dialect.exclude_set_input_sizes
 
-        if include_types is None and exclude_types is None:
+        dbapi = dialect.dbapi
 
-            def _lookup_type(typ):
-                dbtype = typ.dialect_impl(dialect).get_dbapi_type(dbapi)
-                return dbtype
+        def lookup_type(typ):
+            dbtype = typ._unwrapped_dialect_impl(dialect).get_dbapi_type(dbapi)
 
-        else:
-
-            def _lookup_type(typ):
-                # note we get dbtype from the possibly TypeDecorator-wrapped
-                # dialect_impl, but the dialect_impl itself that we use for
-                # include/exclude is the unwrapped version.
-
-                dialect_impl = typ._unwrapped_dialect_impl(dialect)
-
-                dbtype = typ.dialect_impl(dialect).get_dbapi_type(dbapi)
-
-                if (
-                    dbtype is not None
-                    and (
-                        exclude_types is None
-                        or dbtype not in exclude_types
-                        and type(dialect_impl) not in exclude_types
-                    )
-                    and (
-                        include_types is None
-                        or dbtype in include_types
-                        or type(dialect_impl) in include_types
-                    )
-                ):
-                    return dbtype
-                else:
-                    return None
+            if (
+                dbtype is not None
+                and (exclude_types is None or dbtype not in exclude_types)
+                and (include_types is None or dbtype in include_types)
+            ):
+                return dbtype
+            else:
+                return None
 
         inputsizes = {}
+
         literal_execute_params = self.literal_execute_params
 
         for bindparam in self.bind_names:
@@ -1096,10 +1068,10 @@ class SQLCompiler(Compiled):
 
             if bindparam.type._is_tuple_type:
                 inputsizes[bindparam] = [
-                    _lookup_type(typ) for typ in bindparam.type.types
+                    lookup_type(typ) for typ in bindparam.type.types
                 ]
             else:
-                inputsizes[bindparam] = _lookup_type(bindparam.type)
+                inputsizes[bindparam] = lookup_type(bindparam.type)
 
         return inputsizes
 
@@ -2060,7 +2032,25 @@ class SQLCompiler(Compiled):
                 parameter, values
             )
 
-        typ_dialect_impl = parameter.type._unwrapped_dialect_impl(self.dialect)
+        dialect = self.dialect
+        typ_dialect_impl = parameter.type._unwrapped_dialect_impl(dialect)
+
+        if (
+            self.dialect._bind_typing_render_casts
+            and typ_dialect_impl.render_bind_cast
+        ):
+
+            def _render_bindtemplate(name):
+                return self.render_bind_cast(
+                    parameter.type,
+                    typ_dialect_impl,
+                    self.bindtemplate % {"name": name},
+                )
+
+        else:
+
+            def _render_bindtemplate(name):
+                return self.bindtemplate % {"name": name}
 
         if not values:
             to_update = []
@@ -2085,14 +2075,16 @@ class SQLCompiler(Compiled):
                 for i, tuple_element in enumerate(values, 1)
                 for j, value in enumerate(tuple_element, 1)
             ]
+
             replacement_expression = (
-                "VALUES " if self.dialect.tuple_in_values else ""
+                "VALUES " if dialect.tuple_in_values else ""
             ) + ", ".join(
                 "(%s)"
                 % (
                     ", ".join(
-                        self.bindtemplate
-                        % {"name": to_update[i * len(tuple_element) + j][0]}
+                        _render_bindtemplate(
+                            to_update[i * len(tuple_element) + j][0]
+                        )
                         for j, value in enumerate(tuple_element)
                     )
                 )
@@ -2104,7 +2096,7 @@ class SQLCompiler(Compiled):
                 for i, value in enumerate(values, 1)
             ]
             replacement_expression = ", ".join(
-                self.bindtemplate % {"name": key} for key, value in to_update
+                _render_bindtemplate(key) for key, value in to_update
             )
 
         return to_update, replacement_expression
@@ -2373,6 +2365,7 @@ class SQLCompiler(Compiled):
                     m = re.match(
                         r"^(.*)\(__\[POSTCOMPILE_(\S+?)\]\)(.*)$", wrapped
                     )
+                    assert m, "unexpected format for expanding parameter"
                     wrapped = "(__[POSTCOMPILE_%s~~%s~~REPL~~%s~~])" % (
                         m.group(2),
                         m.group(1),
@@ -2460,13 +2453,18 @@ class SQLCompiler(Compiled):
             name,
             post_compile=post_compile,
             expanding=bindparam.expanding,
+            bindparam_type=bindparam.type,
             **kwargs
         )
 
         if bindparam.expanding:
             ret = "(%s)" % ret
+
         return ret
 
+    def render_bind_cast(self, type_, dbapi_type, sqltext):
+        raise NotImplementedError()
+
     def render_literal_bindparam(
         self, bindparam, render_literal_value=NO_ARG, **kw
     ):
@@ -2553,6 +2551,7 @@ class SQLCompiler(Compiled):
         post_compile=False,
         expanding=False,
         escaped_from=None,
+        bindparam_type=None,
         **kw
     ):
 
@@ -2580,8 +2579,18 @@ class SQLCompiler(Compiled):
             self.escaped_bind_names[escaped_from] = name
         if post_compile:
             return "__[POSTCOMPILE_%s]" % name
-        else:
-            return self.bindtemplate % {"name": name}
+
+        ret = self.bindtemplate % {"name": name}
+
+        if (
+            bindparam_type is not None
+            and self.dialect._bind_typing_render_casts
+        ):
+            type_impl = bindparam_type._unwrapped_dialect_impl(self.dialect)
+            if type_impl.render_bind_cast:
+                ret = self.render_bind_cast(bindparam_type, type_impl, ret)
+
+        return ret
 
     def visit_cte(
         self,
diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py
index 82b8f538a..a32b80c95 100644
--- a/lib/sqlalchemy/sql/type_api.py
+++ b/lib/sqlalchemy/sql/type_api.py
@@ -51,6 +51,21 @@ class TypeEngine(Traversible):
     _is_array = False
     _is_type_decorator = False
 
+    render_bind_cast = False
+    """Render bind casts for :attr:`.BindTyping.RENDER_CASTS` mode.
+
+    If True, this type (usually a dialect level impl type) signals
+    to the compiler that a cast should be rendered around a bound parameter
+    for this type.
+
+    .. versionadded:: 2.0
+
+    .. seealso::
+
+        :class:`.BindTyping`
+
+    """
+
     class Comparator(operators.ColumnOperators):
         """Base class for custom comparison operations defined at the
         type level.  See :attr:`.TypeEngine.comparator_factory`.
diff --git a/lib/sqlalchemy/testing/assertsql.py b/lib/sqlalchemy/testing/assertsql.py
index 46fdf6b9b..d9aa3e256 100644
--- a/lib/sqlalchemy/testing/assertsql.py
+++ b/lib/sqlalchemy/testing/assertsql.py
@@ -266,6 +266,10 @@ class DialectSQL(CompiledSQL):
 
     def _dialect_adjusted_statement(self, paramstyle):
         stmt = re.sub(r"[\n\t]", "", self.statement)
+
+        # temporarily escape out PG double colons
+        stmt = stmt.replace("::", "!!")
+
         if paramstyle == "pyformat":
             stmt = re.sub(r":([\w_]+)", r"%(\1)s", stmt)
         else:
@@ -278,6 +282,10 @@ class DialectSQL(CompiledSQL):
             elif paramstyle == "numeric":
                 repl = None
             stmt = re.sub(r":([\w_]+)", repl, stmt)
+
+        # put them back
+        stmt = stmt.replace("!!", "::")
+
         return stmt
 
     def _compare_sql(self, execute_observed, received_statement):
diff --git a/lib/sqlalchemy/testing/suite/test_types.py b/lib/sqlalchemy/testing/suite/test_types.py
index 7989b1e39..82e6fa238 100644
--- a/lib/sqlalchemy/testing/suite/test_types.py
+++ b/lib/sqlalchemy/testing/suite/test_types.py
@@ -480,19 +480,15 @@ class CastTypeDecoratorTest(_LiteralRoundTripFixture, fixtures.TestBase):
             impl = String(50)
             cache_ok = True
 
-            def get_dbapi_type(self, dbapi):
-                return dbapi.NUMBER
-
             def column_expression(self, col):
                 return cast(col, Integer)
 
             def bind_expression(self, col):
-                return cast(col, String(50))
+                return cast(type_coerce(col, Integer), String(50))
 
         return StringAsInt()
 
     def test_special_type(self, metadata, connection, string_as_int):
-
         type_ = string_as_int
 
         t = Table("t", metadata, Column("x", type_))