1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/**
* Implements the `alias this` symbol.
*
* Specification: $(LINK2 https://dlang.org/spec/class.html#alias-this, Alias This)
*
* Copyright: Copyright (C) 1999-2023 by The D Language Foundation, All Rights Reserved
* Authors: $(LINK2 https://www.digitalmars.com, Walter Bright)
* License: $(LINK2 https://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
* Source: $(LINK2 https://github.com/dlang/dmd/blob/master/src/dmd/aliasthis.d, _aliasthis.d)
* Documentation: https://dlang.org/phobos/dmd_aliasthis.html
* Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/aliasthis.d
*/
module dmd.aliasthis;
import core.stdc.stdio;
import dmd.aggregate;
import dmd.dscope;
import dmd.dsymbol;
import dmd.expression;
import dmd.expressionsem;
import dmd.globals;
import dmd.identifier;
import dmd.location;
import dmd.mtype;
import dmd.opover;
import dmd.tokens;
import dmd.visitor;
/***********************************************************
* alias ident this;
*/
extern (C++) final class AliasThis : Dsymbol
{
Identifier ident;
/// The symbol this `alias this` resolves to
Dsymbol sym;
/// Whether this `alias this` is deprecated or not
bool isDeprecated_;
extern (D) this(const ref Loc loc, Identifier ident)
{
super(loc, null); // it's anonymous (no identifier)
this.ident = ident;
}
override AliasThis syntaxCopy(Dsymbol s)
{
assert(!s);
auto at = new AliasThis(loc, ident);
at.comment = comment;
return at;
}
override const(char)* kind() const
{
return "alias this";
}
AliasThis isAliasThis()
{
return this;
}
override void accept(Visitor v)
{
v.visit(this);
}
override bool isDeprecated() const
{
return this.isDeprecated_;
}
}
/*************************************
* Find the `alias this` symbol of e's type.
* Params:
* sc = context
* e = expression forming the `this`
* gag = if true do not print errors, return null instead
* findOnly = don't do further processing like resolving properties,
* i.e. just return plain dotExp() result.
* Returns:
* Expression that is `e.aliasthis`
*/
Expression resolveAliasThis(Scope* sc, Expression e, bool gag = false, bool findOnly = false)
{
import dmd.typesem : dotExp;
for (AggregateDeclaration ad = isAggregate(e.type); ad;)
{
if (ad.aliasthis)
{
Loc loc = e.loc;
Type tthis = (e.op == EXP.type ? e.type : null);
const flags = DotExpFlag.noAliasThis | (gag ? DotExpFlag.gag : 0);
uint olderrors = gag ? global.startGagging() : 0;
e = dotExp(ad.type, sc, e, ad.aliasthis.ident, flags);
if (!e || findOnly)
return gag && global.endGagging(olderrors) ? null : e;
if (tthis && ad.aliasthis.sym.needThis())
{
if (auto ve = e.isVarExp())
{
if (auto fd = ve.var.isFuncDeclaration())
{
// https://issues.dlang.org/show_bug.cgi?id=13009
// Support better match for the overloaded alias this.
bool hasOverloads;
if (auto f = fd.overloadModMatch(loc, tthis, hasOverloads))
{
if (!hasOverloads)
fd = f; // use exact match
e = new VarExp(loc, fd, hasOverloads);
e.type = f.type;
e = new CallExp(loc, e);
goto L1;
}
}
}
/* non-@property function is not called inside typeof(),
* so resolve it ahead.
*/
{
int save = sc.intypeof;
sc.intypeof = 1; // bypass "need this" error check
e = resolveProperties(sc, e);
sc.intypeof = save;
}
L1:
e = new TypeExp(loc, new TypeTypeof(loc, e));
e = e.expressionSemantic(sc);
}
e = resolveProperties(sc, e);
if (!gag)
ad.aliasthis.checkDeprecatedAliasThis(loc, sc);
else if (global.endGagging(olderrors))
e = null;
}
import dmd.dclass : ClassDeclaration;
auto cd = ad.isClassDeclaration();
if ((!e || !ad.aliasthis) && cd && cd.baseClass && cd.baseClass != ClassDeclaration.object)
{
ad = cd.baseClass;
continue;
}
break;
}
return e;
}
/**
* Check if an `alias this` is deprecated
*
* Usually one would use `expression.checkDeprecated(scope, aliasthis)` to
* check if `expression` uses a deprecated `aliasthis`, but this calls
* `toPrettyChars` which lead to the following message:
* "Deprecation: alias this `fullyqualified.aggregate.__anonymous` is deprecated"
*
* Params:
* at = The `AliasThis` object to check
* loc = `Loc` of the expression triggering the access to `at`
* sc = `Scope` of the expression
* (deprecations do not trigger in deprecated scopes)
*
* Returns:
* Whether the alias this was reported as deprecated.
*/
bool checkDeprecatedAliasThis(AliasThis at, const ref Loc loc, Scope* sc)
{
import dmd.errors : deprecation, Classification;
import dmd.dsymbolsem : getMessage;
if (global.params.useDeprecated != DiagnosticReporting.off
&& at.isDeprecated() && !sc.isDeprecated())
{
const(char)* message = null;
for (Dsymbol p = at; p; p = p.parent)
{
message = p.depdecl ? p.depdecl.getMessage() : null;
if (message)
break;
}
if (message)
deprecation(loc, "`alias %s this` is deprecated - %s",
at.sym.toChars(), message);
else
deprecation(loc, "`alias %s this` is deprecated",
at.sym.toChars());
if (auto ti = sc.parent ? sc.parent.isInstantiated() : null)
ti.printInstantiationTrace(Classification.deprecation);
return true;
}
return false;
}
/**************************************
* Check and set 'att' if 't' is a recursive 'alias this' type
* Params:
* att = type reference used to detect recursion
* t = 'alias this' type
*
* Returns:
* Whether the 'alias this' is recursive or not
*/
bool isRecursiveAliasThis(ref Type att, Type t)
{
auto tb = t.toBasetype();
if (att && tb.equivalent(att))
return true;
else if (!att && tb.checkAliasThisRec())
att = tb;
return false;
}
|
