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dtemplate.d
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dtemplate.d
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/**
* Defines `TemplateDeclaration`, `TemplateInstance` and a few utilities
*
* This modules holds the two main template types:
* `TemplateDeclaration`, which is the user-provided declaration of a template,
* and `TemplateInstance`, which is an instance of a `TemplateDeclaration`
* with specific arguments.
*
* Template_Parameter:
* Additionally, the classes for template parameters are defined in this module.
* The base class, `TemplateParameter`, is inherited by:
* - `TemplateTypeParameter`
* - `TemplateThisParameter`
* - `TemplateValueParameter`
* - `TemplateAliasParameter`
* - `TemplateTupleParameter`
*
* Templates_semantic:
* The start of the template instantiation process looks like this:
* - A `TypeInstance` or `TypeIdentifier` is encountered.
* `TypeInstance` have a bang (e.g. `Foo!(arg)`) while `TypeIdentifier` don't.
* - A `TemplateInstance` is instantiated
* - Semantic is run on the `TemplateInstance` (see `dmd.dsymbolsem`)
* - The `TemplateInstance` search for its `TemplateDeclaration`,
* runs semantic on the template arguments and deduce the best match
* among the possible overloads.
* - The `TemplateInstance` search for existing instances with the same
* arguments, and uses it if found.
* - Otherwise, the rest of semantic is run on the `TemplateInstance`.
*
* 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/dtemplate.d, _dtemplate.d)
* Documentation: https://dlang.org/phobos/dmd_dtemplate.html
* Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/dtemplate.d
*/
module dmd.dtemplate;
import core.stdc.stdio;
import core.stdc.string;
import dmd.aggregate;
import dmd.aliasthis;
import dmd.arraytypes;
import dmd.astenums;
import dmd.ast_node;
import dmd.dcast;
import dmd.dclass;
import dmd.declaration;
import dmd.dmangle;
import dmd.dmodule;
import dmd.dscope;
import dmd.dsymbol;
import dmd.dsymbolsem;
import dmd.errors;
import dmd.expression;
import dmd.expressionsem;
import dmd.func;
import dmd.globals;
import dmd.hdrgen;
import dmd.id;
import dmd.identifier;
import dmd.impcnvtab;
import dmd.init;
import dmd.initsem;
import dmd.location;
import dmd.mtype;
import dmd.opover;
import dmd.root.array;
import dmd.common.outbuffer;
import dmd.root.rootobject;
import dmd.semantic2;
import dmd.semantic3;
import dmd.tokens;
import dmd.typesem;
import dmd.visitor;
import dmd.templateparamsem;
//debug = FindExistingInstance; // print debug stats of findExistingInstance
private enum LOG = false;
enum IDX_NOTFOUND = 0x12345678;
pure nothrow @nogc
{
/********************************************
* These functions substitute for dynamic_cast. dynamic_cast does not work
* on earlier versions of gcc.
*/
extern (C++) inout(Expression) isExpression(inout RootObject o)
{
//return dynamic_cast<Expression *>(o);
if (!o || o.dyncast() != DYNCAST.expression)
return null;
return cast(inout(Expression))o;
}
extern (C++) inout(Dsymbol) isDsymbol(inout RootObject o)
{
//return dynamic_cast<Dsymbol *>(o);
if (!o || o.dyncast() != DYNCAST.dsymbol)
return null;
return cast(inout(Dsymbol))o;
}
extern (C++) inout(Type) isType(inout RootObject o)
{
//return dynamic_cast<Type *>(o);
if (!o || o.dyncast() != DYNCAST.type)
return null;
return cast(inout(Type))o;
}
extern (C++) inout(Tuple) isTuple(inout RootObject o)
{
//return dynamic_cast<Tuple *>(o);
if (!o || o.dyncast() != DYNCAST.tuple)
return null;
return cast(inout(Tuple))o;
}
extern (C++) inout(Parameter) isParameter(inout RootObject o)
{
//return dynamic_cast<Parameter *>(o);
if (!o || o.dyncast() != DYNCAST.parameter)
return null;
return cast(inout(Parameter))o;
}
extern (C++) inout(TemplateParameter) isTemplateParameter(inout RootObject o)
{
if (!o || o.dyncast() != DYNCAST.templateparameter)
return null;
return cast(inout(TemplateParameter))o;
}
/**************************************
* Is this Object an error?
*/
extern (C++) bool isError(const RootObject o)
{
if (const t = isType(o))
return (t.ty == Terror);
if (const e = isExpression(o))
return (e.op == EXP.error || !e.type || e.type.ty == Terror);
if (const v = isTuple(o))
return arrayObjectIsError(&v.objects);
const s = isDsymbol(o);
assert(s);
if (s.errors)
return true;
return s.parent ? isError(s.parent) : false;
}
/**************************************
* Are any of the Objects an error?
*/
bool arrayObjectIsError(const Objects* args)
{
foreach (const o; *args)
{
if (isError(o))
return true;
}
return false;
}
/***********************
* Try to get arg as a type.
*/
inout(Type) getType(inout RootObject o)
{
inout t = isType(o);
if (!t)
{
if (inout e = isExpression(o))
return e.type;
}
return t;
}
}
Dsymbol getDsymbol(RootObject oarg)
{
//printf("getDsymbol()\n");
//printf("e %p s %p t %p v %p\n", isExpression(oarg), isDsymbol(oarg), isType(oarg), isTuple(oarg));
if (auto ea = isExpression(oarg))
{
// Try to convert Expression to symbol
if (auto ve = ea.isVarExp())
return ve.var;
else if (auto fe = ea.isFuncExp())
return fe.td ? fe.td : fe.fd;
else if (auto te = ea.isTemplateExp())
return te.td;
else if (auto te = ea.isScopeExp())
return te.sds;
else
return null;
}
else
{
// Try to convert Type to symbol
if (auto ta = isType(oarg))
return ta.toDsymbol(null);
else
return isDsymbol(oarg); // if already a symbol
}
}
private Expression getValue(ref Dsymbol s)
{
if (s)
{
if (VarDeclaration v = s.isVarDeclaration())
{
if (v.storage_class & STC.manifest)
return v.getConstInitializer();
}
}
return null;
}
/***********************
* Try to get value from manifest constant
*/
private Expression getValue(Expression e)
{
if (!e)
return null;
if (auto ve = e.isVarExp())
{
if (auto v = ve.var.isVarDeclaration())
{
if (v.storage_class & STC.manifest)
{
e = v.getConstInitializer();
}
}
}
return e;
}
private Expression getExpression(RootObject o)
{
auto s = isDsymbol(o);
return s ? .getValue(s) : .getValue(isExpression(o));
}
/******************************
* If o1 matches o2, return true.
* Else, return false.
*/
private bool match(RootObject o1, RootObject o2)
{
enum log = false;
static if (log)
{
printf("match() o1 = %p %s (%d), o2 = %p %s (%d)\n",
o1, o1.toChars(), o1.dyncast(), o2, o2.toChars(), o2.dyncast());
}
/* A proper implementation of the various equals() overrides
* should make it possible to just do o1.equals(o2), but
* we'll do that another day.
*/
/* Manifest constants should be compared by their values,
* at least in template arguments.
*/
if (auto t1 = isType(o1))
{
auto t2 = isType(o2);
if (!t2)
goto Lnomatch;
static if (log)
{
printf("\tt1 = %s\n", t1.toChars());
printf("\tt2 = %s\n", t2.toChars());
}
if (!t1.equals(t2))
goto Lnomatch;
goto Lmatch;
}
if (auto e1 = getExpression(o1))
{
auto e2 = getExpression(o2);
if (!e2)
goto Lnomatch;
static if (log)
{
printf("\te1 = %s '%s' %s\n", e1.type ? e1.type.toChars() : "null", EXPtoString(e1.op).ptr, e1.toChars());
printf("\te2 = %s '%s' %s\n", e2.type ? e2.type.toChars() : "null", EXPtoString(e2.op).ptr, e2.toChars());
}
// two expressions can be equal although they do not have the same
// type; that happens when they have the same value. So check type
// as well as expression equality to ensure templates are properly
// matched.
if (!(e1.type && e2.type && e1.type.equals(e2.type)) || !e1.equals(e2))
goto Lnomatch;
goto Lmatch;
}
if (auto s1 = isDsymbol(o1))
{
auto s2 = isDsymbol(o2);
if (!s2)
goto Lnomatch;
static if (log)
{
printf("\ts1 = %s \n", s1.kind(), s1.toChars());
printf("\ts2 = %s \n", s2.kind(), s2.toChars());
}
if (!s1.equals(s2))
goto Lnomatch;
if (s1.parent != s2.parent && !s1.isFuncDeclaration() && !s2.isFuncDeclaration())
goto Lnomatch;
goto Lmatch;
}
if (auto u1 = isTuple(o1))
{
auto u2 = isTuple(o2);
if (!u2)
goto Lnomatch;
static if (log)
{
printf("\tu1 = %s\n", u1.toChars());
printf("\tu2 = %s\n", u2.toChars());
}
if (!arrayObjectMatch(&u1.objects, &u2.objects))
goto Lnomatch;
goto Lmatch;
}
Lmatch:
static if (log)
printf("\t. match\n");
return true;
Lnomatch:
static if (log)
printf("\t. nomatch\n");
return false;
}
/************************************
* Match an array of them.
*/
private bool arrayObjectMatch(Objects* oa1, Objects* oa2)
{
if (oa1 == oa2)
return true;
if (oa1.length != oa2.length)
return false;
immutable oa1dim = oa1.length;
auto oa1d = (*oa1)[].ptr;
auto oa2d = (*oa2)[].ptr;
foreach (j; 0 .. oa1dim)
{
RootObject o1 = oa1d[j];
RootObject o2 = oa2d[j];
if (!match(o1, o2))
{
return false;
}
}
return true;
}
/************************************
* Return hash of Objects.
*/
private size_t arrayObjectHash(Objects* oa1)
{
import dmd.root.hash : mixHash;
size_t hash = 0;
foreach (o1; *oa1)
{
/* Must follow the logic of match()
*/
if (auto t1 = isType(o1))
hash = mixHash(hash, cast(size_t)t1.deco);
else if (auto e1 = getExpression(o1))
hash = mixHash(hash, expressionHash(e1));
else if (auto s1 = isDsymbol(o1))
{
auto fa1 = s1.isFuncAliasDeclaration();
if (fa1)
s1 = fa1.toAliasFunc();
hash = mixHash(hash, mixHash(cast(size_t)cast(void*)s1.getIdent(), cast(size_t)cast(void*)s1.parent));
}
else if (auto u1 = isTuple(o1))
hash = mixHash(hash, arrayObjectHash(&u1.objects));
}
return hash;
}
/************************************
* Computes hash of expression.
* Handles all Expression classes and MUST match their equals method,
* i.e. e1.equals(e2) implies expressionHash(e1) == expressionHash(e2).
*/
private size_t expressionHash(Expression e)
{
import dmd.root.ctfloat : CTFloat;
import dmd.root.hash : calcHash, mixHash;
switch (e.op)
{
case EXP.int64:
return cast(size_t) e.isIntegerExp().getInteger();
case EXP.float64:
return CTFloat.hash(e.isRealExp().value);
case EXP.complex80:
auto ce = e.isComplexExp();
return mixHash(CTFloat.hash(ce.toReal), CTFloat.hash(ce.toImaginary));
case EXP.identifier:
return cast(size_t)cast(void*) e.isIdentifierExp().ident;
case EXP.null_:
return cast(size_t)cast(void*) e.isNullExp().type;
case EXP.string_:
return calcHash(e.isStringExp.peekData());
case EXP.tuple:
{
auto te = e.isTupleExp();
size_t hash = 0;
hash += te.e0 ? expressionHash(te.e0) : 0;
foreach (elem; *te.exps)
hash = mixHash(hash, expressionHash(elem));
return hash;
}
case EXP.arrayLiteral:
{
auto ae = e.isArrayLiteralExp();
size_t hash;
foreach (i; 0 .. ae.elements.length)
hash = mixHash(hash, expressionHash(ae[i]));
return hash;
}
case EXP.assocArrayLiteral:
{
auto ae = e.isAssocArrayLiteralExp();
size_t hash;
foreach (i; 0 .. ae.keys.length)
// reduction needs associative op as keys are unsorted (use XOR)
hash ^= mixHash(expressionHash((*ae.keys)[i]), expressionHash((*ae.values)[i]));
return hash;
}
case EXP.structLiteral:
{
auto se = e.isStructLiteralExp();
size_t hash;
foreach (elem; *se.elements)
hash = mixHash(hash, elem ? expressionHash(elem) : 0);
return hash;
}
case EXP.variable:
return cast(size_t)cast(void*) e.isVarExp().var;
case EXP.function_:
return cast(size_t)cast(void*) e.isFuncExp().fd;
default:
// no custom equals for this expression
assert((&e.equals).funcptr is &RootObject.equals);
// equals based on identity
return cast(size_t)cast(void*) e;
}
}
RootObject objectSyntaxCopy(RootObject o)
{
if (!o)
return null;
if (Type t = isType(o))
return t.syntaxCopy();
if (Expression e = isExpression(o))
return e.syntaxCopy();
return o;
}
extern (C++) final class Tuple : RootObject
{
Objects objects;
extern (D) this() {}
/**
Params:
numObjects = The initial number of objects.
*/
extern (D) this(size_t numObjects)
{
objects.setDim(numObjects);
}
// kludge for template.isType()
override DYNCAST dyncast() const
{
return DYNCAST.tuple;
}
override const(char)* toChars() const
{
return objects.toChars();
}
}
struct TemplatePrevious
{
TemplatePrevious* prev;
Scope* sc;
Objects* dedargs;
}
/***********************************************************
* [mixin] template Identifier (parameters) [Constraint]
* https://dlang.org/spec/template.html
* https://dlang.org/spec/template-mixin.html
*/
extern (C++) final class TemplateDeclaration : ScopeDsymbol
{
import dmd.root.array : Array;
TemplateParameters* parameters; // array of TemplateParameter's
TemplateParameters* origParameters; // originals for Ddoc
Expression constraint;
// Hash table to look up TemplateInstance's of this TemplateDeclaration
TemplateInstance[TemplateInstanceBox] instances;
TemplateDeclaration overnext; // next overloaded TemplateDeclaration
TemplateDeclaration overroot; // first in overnext list
FuncDeclaration funcroot; // first function in unified overload list
Dsymbol onemember; // if !=null then one member of this template
bool literal; // this template declaration is a literal
bool ismixin; // this is a mixin template declaration
bool isstatic; // this is static template declaration
bool isTrivialAliasSeq; /// matches pattern `template AliasSeq(T...) { alias AliasSeq = T; }`
bool isTrivialAlias; /// matches pattern `template Alias(T) { alias Alias = qualifiers(T); }`
bool deprecated_; /// this template declaration is deprecated
Visibility visibility;
// threaded list of previous instantiation attempts on stack
TemplatePrevious* previous;
private Expression lastConstraint; /// the constraint after the last failed evaluation
private Array!Expression lastConstraintNegs; /// its negative parts
private Objects* lastConstraintTiargs; /// template instance arguments for `lastConstraint`
extern (D) this(const ref Loc loc, Identifier ident, TemplateParameters* parameters, Expression constraint, Dsymbols* decldefs, bool ismixin = false, bool literal = false)
{
super(loc, ident);
static if (LOG)
{
printf("TemplateDeclaration(this = %p, id = '%s')\n", this, ident.toChars());
}
version (none)
{
if (parameters)
for (int i = 0; i < parameters.length; i++)
{
TemplateParameter tp = (*parameters)[i];
//printf("\tparameter[%d] = %p\n", i, tp);
TemplateTypeParameter ttp = tp.isTemplateTypeParameter();
if (ttp)
{
printf("\tparameter[%d] = %s : %s\n", i, tp.ident.toChars(), ttp.specType ? ttp.specType.toChars() : "");
}
}
}
this.parameters = parameters;
this.origParameters = parameters;
this.constraint = constraint;
this.members = decldefs;
this.literal = literal;
this.ismixin = ismixin;
this.isstatic = true;
this.visibility = Visibility(Visibility.Kind.undefined);
// Compute in advance for Ddoc's use
// https://issues.dlang.org/show_bug.cgi?id=11153: ident could be NULL if parsing fails.
if (!members || !ident)
return;
Dsymbol s;
if (!Dsymbol.oneMembers(members, &s, ident) || !s)
return;
onemember = s;
s.parent = this;
/* Set isTrivialAliasSeq if this fits the pattern:
* template AliasSeq(T...) { alias AliasSeq = T; }
* or set isTrivialAlias if this fits the pattern:
* template Alias(T) { alias Alias = qualifiers(T); }
*/
if (!(parameters && parameters.length == 1))
return;
auto ad = s.isAliasDeclaration();
if (!ad || !ad.type)
return;
auto ti = ad.type.isTypeIdentifier();
if (!ti || ti.idents.length != 0)
return;
if (auto ttp = (*parameters)[0].isTemplateTupleParameter())
{
if (ti.ident is ttp.ident &&
ti.mod == 0)
{
//printf("found isTrivialAliasSeq %s %s\n", s.toChars(), ad.type.toChars());
isTrivialAliasSeq = true;
}
}
else if (auto ttp = (*parameters)[0].isTemplateTypeParameter())
{
if (ti.ident is ttp.ident)
{
//printf("found isTrivialAlias %s %s\n", s.toChars(), ad.type.toChars());
isTrivialAlias = true;
}
}
}
override TemplateDeclaration syntaxCopy(Dsymbol)
{
//printf("TemplateDeclaration.syntaxCopy()\n");
TemplateParameters* p = null;
if (parameters)
{
p = new TemplateParameters(parameters.length);
foreach (i, ref param; *p)
param = (*parameters)[i].syntaxCopy();
}
return new TemplateDeclaration(loc, ident, p, constraint ? constraint.syntaxCopy() : null, Dsymbol.arraySyntaxCopy(members), ismixin, literal);
}
/**********************************
* Overload existing TemplateDeclaration 'this' with the new one 's'.
* Return true if successful; i.e. no conflict.
*/
override bool overloadInsert(Dsymbol s)
{
static if (LOG)
{
printf("TemplateDeclaration.overloadInsert('%s')\n", s.toChars());
}
FuncDeclaration fd = s.isFuncDeclaration();
if (fd)
{
if (funcroot)
return funcroot.overloadInsert(fd);
funcroot = fd;
return funcroot.overloadInsert(this);
}
// https://issues.dlang.org/show_bug.cgi?id=15795
// if candidate is an alias and its sema is not run then
// insertion can fail because the thing it alias is not known
if (AliasDeclaration ad = s.isAliasDeclaration())
{
if (s._scope)
aliasSemantic(ad, s._scope);
if (ad.aliassym && ad.aliassym is this)
return false;
}
TemplateDeclaration td = s.toAlias().isTemplateDeclaration();
if (!td)
return false;
TemplateDeclaration pthis = this;
TemplateDeclaration* ptd;
for (ptd = &pthis; *ptd; ptd = &(*ptd).overnext)
{
}
td.overroot = this;
*ptd = td;
static if (LOG)
{
printf("\ttrue: no conflict\n");
}
return true;
}
override bool hasStaticCtorOrDtor()
{
return false; // don't scan uninstantiated templates
}
override const(char)* kind() const
{
return (onemember && onemember.isAggregateDeclaration()) ? onemember.kind() : "template";
}
override const(char)* toChars() const
{
return toCharsMaybeConstraints(true);
}
/****************************
* Similar to `toChars`, but does not print the template constraints
*/
const(char)* toCharsNoConstraints() const
{
return toCharsMaybeConstraints(false);
}
const(char)* toCharsMaybeConstraints(bool includeConstraints) const
{
if (literal)
return Dsymbol.toChars();
OutBuffer buf;
HdrGenState hgs;
buf.writestring(ident.toString());
buf.writeByte('(');
foreach (i, const tp; *parameters)
{
if (i)
buf.writestring(", ");
.toCBuffer(tp, &buf, &hgs);
}
buf.writeByte(')');
if (onemember)
{
const FuncDeclaration fd = onemember.isFuncDeclaration();
if (fd && fd.type)
{
TypeFunction tf = cast(TypeFunction)fd.type;
buf.writestring(parametersTypeToChars(tf.parameterList));
}
}
if (includeConstraints &&
constraint)
{
buf.writestring(" if (");
.toCBuffer(constraint, &buf, &hgs);
buf.writeByte(')');
}
return buf.extractChars();
}
override Visibility visible() pure nothrow @nogc @safe
{
return visibility;
}
/****************************
* Check to see if constraint is satisfied.
*/
extern (D) bool evaluateConstraint(TemplateInstance ti, Scope* sc, Scope* paramscope, Objects* dedargs, FuncDeclaration fd)
{
/* Detect recursive attempts to instantiate this template declaration,
* https://issues.dlang.org/show_bug.cgi?id=4072
* void foo(T)(T x) if (is(typeof(foo(x)))) { }
* static assert(!is(typeof(foo(7))));
* Recursive attempts are regarded as a constraint failure.
*/
/* There's a chicken-and-egg problem here. We don't know yet if this template
* instantiation will be a local one (enclosing is set), and we won't know until
* after selecting the correct template. Thus, function we're nesting inside
* is not on the sc scope chain, and this can cause errors in FuncDeclaration.getLevel().
* Workaround the problem by setting a flag to relax the checking on frame errors.
*/
for (TemplatePrevious* p = previous; p; p = p.prev)
{
if (!arrayObjectMatch(p.dedargs, dedargs))
continue;
//printf("recursive, no match p.sc=%p %p %s\n", p.sc, this, this.toChars());
/* It must be a subscope of p.sc, other scope chains are not recursive
* instantiations.
* the chain of enclosing scopes is broken by paramscope (its enclosing
* scope is _scope, but paramscope.callsc is the instantiating scope). So
* it's good enough to check the chain of callsc
*/
for (Scope* scx = paramscope.callsc; scx; scx = scx.callsc)
{
// The first scx might be identical for nested eponymeous templates, e.g.
// template foo() { void foo()() {...} }
if (scx == p.sc && scx !is paramscope.callsc)
return false;
}
/* BUG: should also check for ref param differences
*/
}
TemplatePrevious pr;
pr.prev = previous;
pr.sc = paramscope.callsc;
pr.dedargs = dedargs;
previous = ≺ // add this to threaded list
Scope* scx = paramscope.push(ti);
scx.parent = ti;
scx.tinst = null;
scx.minst = null;
// Set SCOPE.constraint before declaring function parameters for the static condition
// (previously, this was immediately before calling evalStaticCondition), so the
// semantic pass knows not to issue deprecation warnings for these throw-away decls.
// https://issues.dlang.org/show_bug.cgi?id=21831
scx.flags |= SCOPE.constraint;
assert(!ti.symtab);
if (fd)
{
/* Declare all the function parameters as variables and add them to the scope
* Making parameters is similar to FuncDeclaration.semantic3
*/
auto tf = fd.type.isTypeFunction();
scx.parent = fd;
Parameters* fparameters = tf.parameterList.parameters;
const nfparams = tf.parameterList.length;
foreach (i, fparam; tf.parameterList)
{
fparam.storageClass &= (STC.IOR | STC.lazy_ | STC.final_ | STC.TYPECTOR | STC.nodtor);
fparam.storageClass |= STC.parameter;
if (tf.parameterList.varargs == VarArg.typesafe && i + 1 == nfparams)
{
fparam.storageClass |= STC.variadic;
/* Don't need to set STC.scope_ because this will only
* be evaluated at compile time
*/
}
}
foreach (fparam; *fparameters)
{
if (!fparam.ident)
continue;
// don't add it, if it has no name
auto v = new VarDeclaration(loc, fparam.type, fparam.ident, null);
fparam.storageClass |= STC.parameter;
v.storage_class = fparam.storageClass;
v.dsymbolSemantic(scx);
if (!ti.symtab)
ti.symtab = new DsymbolTable();
if (!scx.insert(v))
error("parameter `%s.%s` is already defined", toChars(), v.toChars());
else
v.parent = fd;
}
if (isstatic)
fd.storage_class |= STC.static_;
fd.declareThis(scx);
}
lastConstraint = constraint.syntaxCopy();
lastConstraintTiargs = ti.tiargs;
lastConstraintNegs.setDim(0);
import dmd.staticcond;
assert(ti.inst is null);
ti.inst = ti; // temporary instantiation to enable genIdent()
bool errors;
const bool result = evalStaticCondition(scx, constraint, lastConstraint, errors, &lastConstraintNegs);
if (result || errors)
{
lastConstraint = null;
lastConstraintTiargs = null;
lastConstraintNegs.setDim(0);
}
ti.inst = null;
ti.symtab = null;
scx = scx.pop();
previous = pr.prev; // unlink from threaded list
if (errors)
return false;
return result;
}
/****************************
* Destructively get the error message from the last constraint evaluation
* Params:
* tip = tip to show after printing all overloads
*/
const(char)* getConstraintEvalError(ref const(char)* tip)
{
import dmd.staticcond;
// there will be a full tree view in verbose mode, and more compact list in the usual
const full = global.params.verbose;
uint count;
const msg = visualizeStaticCondition(constraint, lastConstraint, lastConstraintNegs[], full, count);
scope (exit)
{
lastConstraint = null;
lastConstraintTiargs = null;
lastConstraintNegs.setDim(0);
}
if (!msg)
return null;
OutBuffer buf;
assert(parameters && lastConstraintTiargs);
if (parameters.length > 0)
{
formatParamsWithTiargs(*lastConstraintTiargs, buf);
buf.writenl();
}
if (!full)
{
// choosing singular/plural
const s = (count == 1) ?
" must satisfy the following constraint:" :
" must satisfy one of the following constraints:";
buf.writestring(s);
buf.writenl();
// the constraints
buf.writeByte('`');
buf.writestring(msg);
buf.writeByte('`');
}
else
{
buf.writestring(" whose parameters have the following constraints:");
buf.writenl();
const sep = " `~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`";
buf.writestring(sep);
buf.writenl();
// the constraints
buf.writeByte('`');
buf.writestring(msg);
buf.writeByte('`');
buf.writestring(sep);
tip = "not satisfied constraints are marked with `>`";
}
return buf.extractChars();
}
private void formatParamsWithTiargs(ref Objects tiargs, ref OutBuffer buf)
{
buf.writestring(" with `");
// write usual arguments line-by-line
// skips trailing default ones - they are not present in `tiargs`
const bool variadic = isVariadic() !is null;
const end = cast(int)parameters.length - (variadic ? 1 : 0);
uint i;
for (; i < tiargs.length && i < end; i++)
{
if (i > 0)
{
buf.writeByte(',');
buf.writenl();
buf.writestring(" ");
}
write(buf, (*parameters)[i]);
buf.writestring(" = ");
write(buf, tiargs[i]);
}
// write remaining variadic arguments on the last line
if (variadic)
{
if (i > 0)
{
buf.writeByte(',');
buf.writenl();
buf.writestring(" ");
}