Function strip_implicit_coercions

src/backend/nodes/nodeFuncs.c:671–719

* strip_implicit_coercions: remove implicit coercions at top level of tree * * This doesn't modify or copy the input expression tree, just return a * pointer to a suitable place within it. * * Note: there isn't any useful thing we can do with a RowExpr here, so * just return it unchanged, even if it's marked as an implicit coercion. */

 * just return it unchanged, even if it's marked as an implicit coercion.
 */
Node *
strip_implicit_coercions(Node *node)
{
	if (node == NULL)
		return NULL;
	if (IsA(node, FuncExpr))
	{
		FuncExpr   *f = (FuncExpr *) node;

		if (f->funcformat == COERCE_IMPLICIT_CAST)
			return strip_implicit_coercions(linitial(f->args));
	}
	else if (IsA(node, RelabelType))
	{
		RelabelType *r = (RelabelType *) node;

		if (r->relabelformat == COERCE_IMPLICIT_CAST)
			return strip_implicit_coercions((Node *) r->arg);
	}
	else if (IsA(node, CoerceViaIO))
	{
		CoerceViaIO *c = (CoerceViaIO *) node;

		if (c->coerceformat == COERCE_IMPLICIT_CAST)
			return strip_implicit_coercions((Node *) c->arg);
	}
	else if (IsA(node, ArrayCoerceExpr))
	{
		ArrayCoerceExpr *c = (ArrayCoerceExpr *) node;

		if (c->coerceformat == COERCE_IMPLICIT_CAST)
			return strip_implicit_coercions((Node *) c->arg);
	}
	else if (IsA(node, ConvertRowtypeExpr))
	{
		ConvertRowtypeExpr *c = (ConvertRowtypeExpr *) node;

		if (c->convertformat == COERCE_IMPLICIT_CAST)
			return strip_implicit_coercions((Node *) c->arg);
	}
	else if (IsA(node, CoerceToDomain))
	{
		CoerceToDomain *c = (CoerceToDomain *) node;

		if (c->coercionformat == COERCE_IMPLICIT_CAST)
			return strip_implicit_coercions((Node *) c->arg);
	}
	return node;
}

/*
 * expression_returns_set