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#![allow(dead_code)]
use super::super::constant::Value;
use super::super::objects::TypeKey;
use super::super::operand::{Operand, OperandMode};
use super::super::typ::{self, BasicType, Type};
use super::check::{Checker, FilesContext};
use std::char;
impl<'a> Checker<'a> {
pub fn conversion(&mut self, x: &mut Operand, t: TypeKey, fctx: &mut FilesContext) {
let constv = match &mut x.mode {
OperandMode::Constant(v) => Some(v),
_ => None,
};
let const_arg = constv.is_some();
let o = &self.tc_objs;
let xtype = x.typ.unwrap();
let ok = if const_arg && typ::is_const_type(t, o) {
// constant conversion
let v = constv.unwrap();
let tval = self.otype(t).underlying_val(o);
let basic = tval.try_as_basic().unwrap();
let clone = v.clone();
if clone.representable(basic, Some(v)) {
true
} else if typ::is_integer(xtype, o) && tval.is_string(o) {
let mut s = "\u{FFFD}".to_string();
let (i, exact) = v.int_as_i64();
if exact {
if let Some(c) = char::from_u32(i as u32) {
s = c.to_string()
}
}
*v = Value::with_str(s);
true
} else {
false
}
} else if self.convertable_to(x, t) {
// non-constant conversion
x.mode = OperandMode::Value;
true
} else {
false
};
if !ok {
let xd = self.new_dis(x);
let td = self.new_dis(&t);
self.error(xd.pos(), format!("cannot convert {} to {}", xd, td));
x.mode = OperandMode::Invalid;
return;
}
// The conversion argument types are final. For untyped values the
// conversion provides the type, per the spec: "A constant may be
// given a type explicitly by a constant declaration or conversion,...".
if typ::is_untyped(xtype, self.tc_objs) {
// - For conversions to interfaces, use the argument's default type.
// - For conversions of untyped constants to non-constant types, also
// use the default type (e.g., []byte("foo") should report string
// not []byte as type for the constant "foo").
// - Keep untyped nil for untyped nil arguments.
// - For integer to string conversions, keep the argument type.
let final_t = if typ::is_interface(t, o) || const_arg && !typ::is_const_type(t, o) {
typ::untyped_default_type(xtype, o)
} else if typ::is_integer(xtype, o) && typ::is_string(t, o) {
xtype
} else {
t
};
self.update_expr_type(x.expr.as_ref().unwrap(), final_t, true, fctx);
}
x.typ = Some(t);
}
// convertible_to returns if x is convertable to t.
// The check parameter may be nil if convertibleTo is invoked through an
// exported API call, i.e., when all methods have been type-checked.
pub fn convertable_to(&self, x: &Operand, t: TypeKey) -> bool {
let o = &self.tc_objs;
// "x is assignable to t"
if x.assignable_to(t, None, o) {
return true;
}
// "x's type and t have identical underlying types if tags are ignored"
let v = x.typ.unwrap();
let vu = typ::underlying_type(v, o);
let tu = typ::underlying_type(t, o);
if typ::identical_ignore_tags(Some(vu), Some(tu), o) {
return true;
}
let vval = self.otype(v);
let tval = self.otype(t);
let vuval = self.otype(vu);
let tuval = self.otype(tu);
// "x's type and t are unnamed pointer types and their pointer base types
// have identical underlying types if tags are ignored"
if let Some(vdetail) = vval.try_as_pointer() {
if let Some(tdetail) = tval.try_as_pointer() {
let vu = typ::underlying_type(vdetail.base(), o);
let tu = typ::underlying_type(tdetail.base(), o);
if typ::identical_ignore_tags(Some(vu), Some(tu), o) {
return true;
}
}
}
// "x's type and t are both integer or floating point types"
if (vval.is_integer(o) || vval.is_float(o)) && (tval.is_integer(o) || tval.is_float(o)) {
return true;
}
// "x's type and t are both complex types"
if vval.is_complex(o) || tval.is_complex(o) {
return true;
}
// "x is an integer or a slice of bytes or runes and t is a string type"
if (vval.is_integer(o) || self.is_bytes_or_runes(vuval)) && tval.is_string(o) {
return true;
}
// "x is a string and T is a slice of bytes or runes"
if vval.is_string(o) && self.is_bytes_or_runes(tuval) {
return true;
}
// package unsafe:
// "any pointer or value of underlying type uintptr can be converted into a unsafe.Pointer"
if (self.is_pointer(vuval) || self.is_uintptr(vuval)) && self.is_unsafe_pointer(tval) {
return true;
}
// "and vice versa"
if (self.is_pointer(tuval) || self.is_uintptr(tuval)) && self.is_unsafe_pointer(vval) {
return true;
}
false
}
fn is_uintptr(&self, t: &Type) -> bool {
if let Some(detail) = t.underlying_val(self.tc_objs).try_as_basic() {
return detail.typ() == BasicType::Uintptr;
}
false
}
fn is_unsafe_pointer(&self, t: &Type) -> bool {
if let Some(detail) = t.underlying_val(self.tc_objs).try_as_basic() {
return detail.typ() == BasicType::UnsafePointer;
}
false
}
fn is_pointer(&self, t: &Type) -> bool {
t.underlying_val(self.tc_objs).try_as_pointer().is_some()
}
fn is_bytes_or_runes(&self, t: &Type) -> bool {
if let Some(detail) = t.try_as_slice() {
if let Some(b) = self
.otype(detail.elem())
.underlying_val(self.tc_objs)
.try_as_basic()
{
return b.typ() == BasicType::Byte || b.typ() == BasicType::Rune;
}
}
false
}
}