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dcast.d
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dcast.d
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/**
* Semantic analysis for cast-expressions.
*
* Copyright: Copyright (C) 1999-2021 by The D Language Foundation, All Rights Reserved
* Authors: $(LINK2 http://www.digitalmars.com, Walter Bright)
* License: $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
* Source: $(LINK2 https://github.com/dlang/dmd/blob/master/src/dmd/dcast.d, _dcast.d)
* Documentation: https://dlang.org/phobos/dmd_dcast.html
* Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/dcast.d
*/
module dmd.dcast;
import core.stdc.stdio;
import core.stdc.string;
import dmd.aggregate;
import dmd.aliasthis;
import dmd.arrayop;
import dmd.arraytypes;
import dmd.astenums;
import dmd.dclass;
import dmd.declaration;
import dmd.dscope;
import dmd.dstruct;
import dmd.dsymbol;
import dmd.errors;
import dmd.escape;
import dmd.expression;
import dmd.expressionsem;
import dmd.func;
import dmd.globals;
import dmd.impcnvtab;
import dmd.id;
import dmd.importc;
import dmd.init;
import dmd.intrange;
import dmd.mtype;
import dmd.opover;
import dmd.root.ctfloat;
import dmd.common.outbuffer;
import dmd.root.rmem;
import dmd.tokens;
import dmd.typesem;
import dmd.utf;
import dmd.visitor;
enum LOG = false;
/**
* Attempt to implicitly cast the expression into type `t`.
*
* This routine will change `e`. To check the matching level,
* use `implicitConvTo`.
*
* Params:
* e = Expression that is to be casted
* sc = Current scope
* t = Expected resulting type
*
* Returns:
* The resulting casted expression (mutating `e`), or `ErrorExp`
* if such an implicit conversion is not possible.
*/
Expression implicitCastTo(Expression e, Scope* sc, Type t)
{
extern (C++) final class ImplicitCastTo : Visitor
{
alias visit = Visitor.visit;
public:
Type t;
Scope* sc;
Expression result;
extern (D) this(Scope* sc, Type t)
{
this.sc = sc;
this.t = t;
}
override void visit(Expression e)
{
//printf("Expression.implicitCastTo(%s of type %s) => %s\n", e.toChars(), e.type.toChars(), t.toChars());
if (const match = (sc && sc.flags & SCOPE.Cfile) ? e.cimplicitConvTo(t) : e.implicitConvTo(t))
{
if (match == MATCH.constant && (e.type.constConv(t) || !e.isLvalue() && e.type.equivalent(t)))
{
/* Do not emit CastExp for const conversions and
* unique conversions on rvalue.
*/
result = e.copy();
result.type = t;
return;
}
auto ad = isAggregate(e.type);
if (ad && ad.aliasthis)
{
auto ts = ad.type.isTypeStruct();
const adMatch = ts
? ts.implicitConvToWithoutAliasThis(t)
: ad.type.isTypeClass().implicitConvToWithoutAliasThis(t);
if (!adMatch)
{
Type tob = t.toBasetype();
Type t1b = e.type.toBasetype();
if (ad != isAggregate(tob))
{
if (t1b.ty == Tclass && tob.ty == Tclass)
{
ClassDeclaration t1cd = t1b.isClassHandle();
ClassDeclaration tocd = tob.isClassHandle();
int offset;
if (tocd.isBaseOf(t1cd, &offset))
{
result = new CastExp(e.loc, e, t);
result.type = t;
return;
}
}
/* Forward the cast to our alias this member, rewrite to:
* cast(to)e1.aliasthis
*/
result = resolveAliasThis(sc, e);
result = result.castTo(sc, t);
return;
}
}
}
result = e.castTo(sc, t);
return;
}
result = e.optimize(WANTvalue);
if (result != e)
{
result.accept(this);
return;
}
if (t.ty != Terror && e.type.ty != Terror)
{
if (!t.deco)
{
e.error("forward reference to type `%s`", t.toChars());
}
else
{
//printf("type %p ty %d deco %p\n", type, type.ty, type.deco);
//type = type.typeSemantic(loc, sc);
//printf("type %s t %s\n", type.deco, t.deco);
auto ts = toAutoQualChars(e.type, t);
e.error("cannot implicitly convert expression `%s` of type `%s` to `%s`",
e.toChars(), ts[0], ts[1]);
}
}
result = ErrorExp.get();
}
override void visit(StringExp e)
{
//printf("StringExp::implicitCastTo(%s of type %s) => %s\n", e.toChars(), e.type.toChars(), t.toChars());
visit(cast(Expression)e);
if (auto se = result.isStringExp())
{
// Retain polysemous nature if it started out that way
se.committed = e.committed;
}
}
override void visit(ErrorExp e)
{
result = e;
}
override void visit(FuncExp e)
{
//printf("FuncExp::implicitCastTo type = %p %s, t = %s\n", e.type, e.type ? e.type.toChars() : NULL, t.toChars());
FuncExp fe;
if (e.matchType(t, sc, &fe) > MATCH.nomatch)
{
result = fe;
return;
}
visit(cast(Expression)e);
}
override void visit(ArrayLiteralExp e)
{
visit(cast(Expression)e);
Type tb = result.type.toBasetype();
if (auto ta = tb.isTypeDArray())
if (global.params.useTypeInfo && Type.dtypeinfo)
semanticTypeInfo(sc, ta.next);
}
override void visit(SliceExp e)
{
visit(cast(Expression)e);
if (auto se = result.isSliceExp())
if (auto ale = se.e1.isArrayLiteralExp())
{
Type tb = t.toBasetype();
Type tx = (tb.ty == Tsarray)
? tb.nextOf().sarrayOf(ale.elements ? ale.elements.dim : 0)
: tb.nextOf().arrayOf();
se.e1 = ale.implicitCastTo(sc, tx);
}
}
}
scope ImplicitCastTo v = new ImplicitCastTo(sc, t);
e.accept(v);
return v.result;
}
/**
* Checks whether or not an expression can be implicitly converted
* to type `t`.
*
* Unlike `implicitCastTo`, this routine does not perform the actual cast,
* but only checks up to what `MATCH` level the conversion would be possible.
*
* Params:
* e = Expression that is to be casted
* t = Expected resulting type
*
* Returns:
* The `MATCH` level between `e.type` and `t`.
*/
MATCH implicitConvTo(Expression e, Type t)
{
extern (C++) final class ImplicitConvTo : Visitor
{
alias visit = Visitor.visit;
public:
Type t;
MATCH result;
extern (D) this(Type t)
{
this.t = t;
result = MATCH.nomatch;
}
override void visit(Expression e)
{
version (none)
{
printf("Expression::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
//static int nest; if (++nest == 10) assert(0);
if (t == Type.terror)
return;
if (!e.type)
{
e.error("`%s` is not an expression", e.toChars());
e.type = Type.terror;
}
Expression ex = e.optimize(WANTvalue);
if (ex.type.equals(t))
{
result = MATCH.exact;
return;
}
if (ex != e)
{
//printf("\toptimized to %s of type %s\n", e.toChars(), e.type.toChars());
result = ex.implicitConvTo(t);
return;
}
MATCH match = e.type.implicitConvTo(t);
if (match != MATCH.nomatch)
{
result = match;
return;
}
/* See if we can do integral narrowing conversions
*/
if (e.type.isintegral() && t.isintegral() && e.type.isTypeBasic() && t.isTypeBasic())
{
IntRange src = getIntRange(e);
IntRange target = IntRange.fromType(t);
if (target.contains(src))
{
result = MATCH.convert;
return;
}
}
}
/******
* Given expression e of type t, see if we can implicitly convert e
* to type tprime, where tprime is type t with mod bits added.
* Returns:
* match level
*/
static MATCH implicitMod(Expression e, Type t, MOD mod)
{
Type tprime;
if (t.ty == Tpointer)
tprime = t.nextOf().castMod(mod).pointerTo();
else if (t.ty == Tarray)
tprime = t.nextOf().castMod(mod).arrayOf();
else if (t.ty == Tsarray)
tprime = t.nextOf().castMod(mod).sarrayOf(t.size() / t.nextOf().size());
else
tprime = t.castMod(mod);
return e.implicitConvTo(tprime);
}
static MATCH implicitConvToAddMin(BinExp e, Type t)
{
/* Is this (ptr +- offset)? If so, then ask ptr
* if the conversion can be done.
* This is to support doing things like implicitly converting a mutable unique
* pointer to an immutable pointer.
*/
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
if (typeb.ty != Tpointer || tb.ty != Tpointer)
return MATCH.nomatch;
Type t1b = e.e1.type.toBasetype();
Type t2b = e.e2.type.toBasetype();
if (t1b.ty == Tpointer && t2b.isintegral() && t1b.equivalent(tb))
{
// ptr + offset
// ptr - offset
MATCH m = e.e1.implicitConvTo(t);
return (m > MATCH.constant) ? MATCH.constant : m;
}
if (t2b.ty == Tpointer && t1b.isintegral() && t2b.equivalent(tb))
{
// offset + ptr
MATCH m = e.e2.implicitConvTo(t);
return (m > MATCH.constant) ? MATCH.constant : m;
}
return MATCH.nomatch;
}
override void visit(AddExp e)
{
version (none)
{
printf("AddExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result == MATCH.nomatch)
result = implicitConvToAddMin(e, t);
}
override void visit(MinExp e)
{
version (none)
{
printf("MinExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result == MATCH.nomatch)
result = implicitConvToAddMin(e, t);
}
override void visit(IntegerExp e)
{
version (none)
{
printf("IntegerExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
MATCH m = e.type.implicitConvTo(t);
if (m >= MATCH.constant)
{
result = m;
return;
}
TY ty = e.type.toBasetype().ty;
TY toty = t.toBasetype().ty;
TY oldty = ty;
if (m == MATCH.nomatch && t.ty == Tenum)
return;
if (auto tv = t.isTypeVector())
{
TypeBasic tb = tv.elementType();
if (tb.ty == Tvoid)
return;
toty = tb.ty;
}
switch (ty)
{
case Tbool:
case Tint8:
case Tchar:
case Tuns8:
case Tint16:
case Tuns16:
case Twchar:
ty = Tint32;
break;
case Tdchar:
ty = Tuns32;
break;
default:
break;
}
// Only allow conversion if no change in value
immutable dinteger_t value = e.toInteger();
bool isLosslesslyConvertibleToFP(T)()
{
if (e.type.isunsigned())
{
const f = cast(T) value;
return cast(dinteger_t) f == value;
}
const f = cast(T) cast(sinteger_t) value;
return cast(sinteger_t) f == cast(sinteger_t) value;
}
switch (toty)
{
case Tbool:
if ((value & 1) != value)
return;
break;
case Tint8:
if (ty == Tuns64 && value & ~0x7FU)
return;
else if (cast(byte)value != value)
return;
break;
case Tchar:
if ((oldty == Twchar || oldty == Tdchar) && value > 0x7F)
return;
goto case Tuns8;
case Tuns8:
//printf("value = %llu %llu\n", (dinteger_t)(unsigned char)value, value);
if (cast(ubyte)value != value)
return;
break;
case Tint16:
if (ty == Tuns64 && value & ~0x7FFFU)
return;
else if (cast(short)value != value)
return;
break;
case Twchar:
if (oldty == Tdchar && value > 0xD7FF && value < 0xE000)
return;
goto case Tuns16;
case Tuns16:
if (cast(ushort)value != value)
return;
break;
case Tint32:
if (ty == Tuns32)
{
}
else if (ty == Tuns64 && value & ~0x7FFFFFFFU)
return;
else if (cast(int)value != value)
return;
break;
case Tuns32:
if (ty == Tint32)
{
}
else if (cast(uint)value != value)
return;
break;
case Tdchar:
if (value > 0x10FFFFU)
return;
break;
case Tfloat32:
if (!isLosslesslyConvertibleToFP!float)
return;
break;
case Tfloat64:
if (!isLosslesslyConvertibleToFP!double)
return;
break;
case Tfloat80:
if (!isLosslesslyConvertibleToFP!real_t)
return;
break;
case Tpointer:
//printf("type = %s\n", type.toBasetype()->toChars());
//printf("t = %s\n", t.toBasetype()->toChars());
if (ty == Tpointer && e.type.toBasetype().nextOf().ty == t.toBasetype().nextOf().ty)
{
/* Allow things like:
* const char* P = cast(char *)3;
* char* q = P;
*/
break;
}
goto default;
default:
visit(cast(Expression)e);
return;
}
//printf("MATCH.convert\n");
result = MATCH.convert;
}
override void visit(ErrorExp e)
{
// no match
}
override void visit(NullExp e)
{
version (none)
{
printf("NullExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
if (e.type.equals(t))
{
result = MATCH.exact;
return;
}
/* Allow implicit conversions from immutable to mutable|const,
* and mutable to immutable. It works because, after all, a null
* doesn't actually point to anything.
*/
if (t.equivalent(e.type))
{
result = MATCH.constant;
return;
}
visit(cast(Expression)e);
}
override void visit(StructLiteralExp e)
{
version (none)
{
printf("StructLiteralExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result != MATCH.nomatch)
return;
if (e.type.ty == t.ty && e.type.isTypeStruct() && e.type.isTypeStruct().sym == t.isTypeStruct().sym)
{
result = MATCH.constant;
foreach (i, el; (*e.elements)[])
{
if (!el)
continue;
Type te = e.sd.fields[i].type.addMod(t.mod);
MATCH m2 = el.implicitConvTo(te);
//printf("\t%s => %s, match = %d\n", el.toChars(), te.toChars(), m2);
if (m2 < result)
result = m2;
}
}
}
override void visit(StringExp e)
{
version (none)
{
printf("StringExp::implicitConvTo(this=%s, committed=%d, type=%s, t=%s)\n", e.toChars(), e.committed, e.type.toChars(), t.toChars());
}
if (!e.committed && t.ty == Tpointer && t.nextOf().ty == Tvoid)
return;
if (!(e.type.ty == Tsarray || e.type.ty == Tarray || e.type.ty == Tpointer))
return visit(cast(Expression)e);
TY tyn = e.type.nextOf().ty;
if (!tyn.isSomeChar)
return visit(cast(Expression)e);
switch (t.ty)
{
case Tsarray:
if (e.type.ty == Tsarray)
{
TY tynto = t.nextOf().ty;
if (tynto == tyn)
{
if (e.type.isTypeSArray().dim.toInteger() == t.isTypeSArray().dim.toInteger())
{
result = MATCH.exact;
}
return;
}
if (tynto.isSomeChar)
{
if (e.committed && tynto != tyn)
return;
size_t fromlen = e.numberOfCodeUnits(tynto);
size_t tolen = cast(size_t)t.isTypeSArray().dim.toInteger();
if (tolen < fromlen)
return;
if (tolen != fromlen)
{
// implicit length extending
result = MATCH.convert;
return;
}
}
if (!e.committed && tynto.isSomeChar)
{
result = MATCH.exact;
return;
}
}
else if (e.type.ty == Tarray)
{
TY tynto = t.nextOf().ty;
if (tynto.isSomeChar)
{
if (e.committed && tynto != tyn)
return;
size_t fromlen = e.numberOfCodeUnits(tynto);
size_t tolen = cast(size_t)t.isTypeSArray().dim.toInteger();
if (tolen < fromlen)
return;
if (tolen != fromlen)
{
// implicit length extending
result = MATCH.convert;
return;
}
}
if (tynto == tyn)
{
result = MATCH.exact;
return;
}
if (!e.committed && tynto.isSomeChar)
{
result = MATCH.exact;
return;
}
}
goto case; /+ fall through +/
case Tarray:
case Tpointer:
Type tn = t.nextOf();
MATCH m = MATCH.exact;
if (e.type.nextOf().mod != tn.mod)
{
// https://issues.dlang.org/show_bug.cgi?id=16183
if (!tn.isConst() && !tn.isImmutable())
return;
m = MATCH.constant;
}
if (!e.committed)
{
switch (tn.ty)
{
case Tchar:
if (e.postfix == 'w' || e.postfix == 'd')
m = MATCH.convert;
result = m;
return;
case Twchar:
if (e.postfix != 'w')
m = MATCH.convert;
result = m;
return;
case Tdchar:
if (e.postfix != 'd')
m = MATCH.convert;
result = m;
return;
case Tenum:
if (tn.isTypeEnum().sym.isSpecial())
{
/* Allow string literal -> const(wchar_t)[]
*/
if (TypeBasic tob = tn.toBasetype().isTypeBasic())
result = tn.implicitConvTo(tob);
return;
}
break;
default:
break;
}
}
break;
default:
break;
}
visit(cast(Expression)e);
}
override void visit(ArrayLiteralExp e)
{
version (none)
{
printf("ArrayLiteralExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
if ((tb.ty == Tarray || tb.ty == Tsarray) &&
(typeb.ty == Tarray || typeb.ty == Tsarray))
{
result = MATCH.exact;
Type typen = typeb.nextOf().toBasetype();
if (auto tsa = tb.isTypeSArray())
{
if (e.elements.dim != tsa.dim.toInteger())
result = MATCH.nomatch;
}
Type telement = tb.nextOf();
if (!e.elements.dim)
{
if (typen.ty != Tvoid)
result = typen.implicitConvTo(telement);
}
else
{
if (e.basis)
{
MATCH m = e.basis.implicitConvTo(telement);
if (m < result)
result = m;
}
for (size_t i = 0; i < e.elements.dim; i++)
{
Expression el = (*e.elements)[i];
if (result == MATCH.nomatch)
break;
if (!el)
continue;
MATCH m = el.implicitConvTo(telement);
if (m < result)
result = m; // remember worst match
}
}
if (!result)
result = e.type.implicitConvTo(t);
return;
}
else if (tb.ty == Tvector && (typeb.ty == Tarray || typeb.ty == Tsarray))
{
result = MATCH.exact;
// Convert array literal to vector type
TypeVector tv = tb.isTypeVector();
TypeSArray tbase = tv.basetype.isTypeSArray();
assert(tbase);
const edim = e.elements.dim;
const tbasedim = tbase.dim.toInteger();
if (edim > tbasedim)
{
result = MATCH.nomatch;
return;
}
Type telement = tv.elementType();
if (edim < tbasedim)
{
Expression el = typeb.nextOf.defaultInitLiteral(e.loc);
MATCH m = el.implicitConvTo(telement);
if (m < result)
result = m; // remember worst match
}
foreach (el; (*e.elements)[])
{
MATCH m = el.implicitConvTo(telement);
if (m < result)
result = m; // remember worst match
if (result == MATCH.nomatch)
break; // no need to check for worse
}
return;
}
visit(cast(Expression)e);
}
override void visit(AssocArrayLiteralExp e)
{
auto taa = t.toBasetype().isTypeAArray();
Type typeb = e.type.toBasetype();
if (!(taa && typeb.ty == Taarray))
return visit(cast(Expression)e);
result = MATCH.exact;
foreach (i, el; (*e.keys)[])
{
MATCH m = el.implicitConvTo(taa.index);
if (m < result)
result = m; // remember worst match
if (result == MATCH.nomatch)
break; // no need to check for worse
el = (*e.values)[i];
m = el.implicitConvTo(taa.nextOf());
if (m < result)
result = m; // remember worst match
if (result == MATCH.nomatch)
break; // no need to check for worse
}
}
override void visit(CallExp e)
{
enum LOG = false;
static if (LOG)
{
printf("CallExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result != MATCH.nomatch)
return;
/* Allow the result of strongly pure functions to
* convert to immutable
*/
if (e.f &&
(global.params.useDIP1000 != FeatureState.enabled || // lots of legacy code breaks with the following purity check
e.f.isPure() >= PURE.strong ||
// Special case exemption for Object.dup() which we assume is implemented correctly
e.f.ident == Id.dup &&
e.f.toParent2() == ClassDeclaration.object.toParent()) &&
e.f.isReturnIsolated() // check isReturnIsolated last, because it is potentially expensive.
)
{
result = e.type.immutableOf().implicitConvTo(t);
if (result > MATCH.constant) // Match level is MATCH.constant at best.
result = MATCH.constant;
return;
}
/* Conversion is 'const' conversion if:
* 1. function is pure (weakly pure is ok)
* 2. implicit conversion only fails because of mod bits
* 3. each function parameter can be implicitly converted to the mod bits
*/
auto tf = (e.f ? e.f.type : e.e1.type).toBasetype().isTypeFunction();
if (!tf)
return;
if (tf.purity == PURE.impure)
return;
if (e.f && e.f.isNested())
return;
/* See if fail only because of mod bits.
*
* https://issues.dlang.org/show_bug.cgi?id=14155
* All pure functions can access global immutable data.
* So the returned pointer may refer an immutable global data,
* and then the returned pointer that points non-mutable object
* cannot be unique pointer.
*
* Example:
* immutable g;
* static this() { g = 1; }
* const(int*) foo() pure { return &g; }
* void test() {
* immutable(int*) ip = foo(); // OK
* int* mp = foo(); // should be disallowed
* }
*/
if (e.type.immutableOf().implicitConvTo(t) < MATCH.constant && e.type.addMod(MODFlags.shared_).implicitConvTo(t) < MATCH.constant && e.type.implicitConvTo(t.addMod(MODFlags.shared_)) < MATCH.constant)
{
return;
}
// Allow a conversion to immutable type, or
// conversions of mutable types between thread-local and shared.
/* Get mod bits of what we're converting to
*/
Type tb = t.toBasetype();
MOD mod = tb.mod;
if (tf.isref)
{
}
else
{
if (Type ti = getIndirection(t))
mod = ti.mod;
}
static if (LOG)
{
printf("mod = x%x\n", mod);
}
if (mod & MODFlags.wild)
return; // not sure what to do with this
/* Apply mod bits to each function parameter,
* and see if we can convert the function argument to the modded type
*/
size_t nparams = tf.parameterList.length;
size_t j = tf.isDstyleVariadic(); // if TypeInfoArray was prepended
if (auto dve = e.e1.isDotVarExp())
{
/* Treat 'this' as just another function argument
*/
Type targ = dve.e1.type;
if (targ.constConv(targ.castMod(mod)) == MATCH.nomatch)
return;
}
foreach (const i; j .. e.arguments.dim)
{
Expression earg = (*e.arguments)[i];
Type targ = earg.type.toBasetype();
static if (LOG)
{
printf("[%d] earg: %s, targ: %s\n", cast(int)i, earg.toChars(), targ.toChars());
}
if (i - j < nparams)
{
Parameter fparam = tf.parameterList[i - j];
if (fparam.storageClass & STC.lazy_)
return; // not sure what to do with this
Type tparam = fparam.type;
if (!tparam)
continue;
if (fparam.isReference())
{
if (targ.constConv(tparam.castMod(mod)) == MATCH.nomatch)
return;
continue;
}
}
static if (LOG)
{
printf("[%d] earg: %s, targm: %s\n", cast(int)i, earg.toChars(), targ.addMod(mod).toChars());
}
if (implicitMod(earg, targ, mod) == MATCH.nomatch)
return;
}
/* Success
*/
result = MATCH.constant;
}
override void visit(AddrExp e)
{
version (none)
{
printf("AddrExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
result = e.type.implicitConvTo(t);
//printf("\tresult = %d\n", result);
if (result != MATCH.nomatch)
return;
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
// Look for pointers to functions where the functions are overloaded.
if (e.e1.op == TOK.overloadSet &&
(tb.ty == Tpointer || tb.ty == Tdelegate) && tb.nextOf().ty == Tfunction)
{
OverExp eo = e.e1.isOverExp();