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semantic3.d
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semantic3.d
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/**
* Performs the semantic3 stage, which deals with function bodies.
*
* Copyright: Copyright (C) 1999-2022 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/semantic3.d, _semantic3.d)
* Documentation: https://dlang.org/phobos/dmd_semantic3.html
* Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/semantic3.d
*/
module dmd.semantic3;
import core.stdc.stdio;
import core.stdc.string;
import dmd.aggregate;
import dmd.aliasthis;
import dmd.arraytypes;
import dmd.astcodegen;
import dmd.astenums;
import dmd.attrib;
import dmd.blockexit;
import dmd.clone;
import dmd.ctorflow;
import dmd.dcast;
import dmd.dclass;
import dmd.declaration;
import dmd.denum;
import dmd.dimport;
import dmd.dinterpret;
import dmd.dmodule;
import dmd.dscope;
import dmd.dstruct;
import dmd.dsymbol;
import dmd.dsymbolsem;
import dmd.dtemplate;
import dmd.dversion;
import dmd.errors;
import dmd.escape;
import dmd.expression;
import dmd.expressionsem;
import dmd.func;
import dmd.globals;
import dmd.id;
import dmd.identifier;
import dmd.init;
import dmd.initsem;
import dmd.hdrgen;
import dmd.mtype;
import dmd.nogc;
import dmd.nspace;
import dmd.ob;
import dmd.objc;
import dmd.opover;
import dmd.parse;
import dmd.root.filename;
import dmd.common.outbuffer;
import dmd.root.rmem;
import dmd.root.rootobject;
import dmd.root.utf;
import dmd.sideeffect;
import dmd.statementsem;
import dmd.staticassert;
import dmd.tokens;
import dmd.semantic2;
import dmd.statement;
import dmd.target;
import dmd.templateparamsem;
import dmd.typesem;
import dmd.visitor;
enum LOG = false;
/*************************************
* Does semantic analysis on function bodies.
*/
extern(C++) void semantic3(Dsymbol dsym, Scope* sc)
{
scope v = new Semantic3Visitor(sc);
dsym.accept(v);
}
private extern(C++) final class Semantic3Visitor : Visitor
{
alias visit = Visitor.visit;
Scope* sc;
this(Scope* sc)
{
this.sc = sc;
}
override void visit(Dsymbol) {}
override void visit(TemplateInstance tempinst)
{
static if (LOG)
{
printf("TemplateInstance.semantic3('%s'), semanticRun = %d\n", tempinst.toChars(), tempinst.semanticRun);
}
//if (toChars()[0] == 'D') *(char*)0=0;
if (tempinst.semanticRun >= PASS.semantic3)
return;
tempinst.semanticRun = PASS.semantic3;
if (tempinst.errors || !tempinst.members)
return;
TemplateDeclaration tempdecl = tempinst.tempdecl.isTemplateDeclaration();
assert(tempdecl);
sc = tempdecl._scope;
sc = sc.push(tempinst.argsym);
sc = sc.push(tempinst);
sc.tinst = tempinst;
sc.minst = tempinst.minst;
int needGagging = (tempinst.gagged && !global.gag);
uint olderrors = global.errors;
int oldGaggedErrors = -1; // dead-store to prevent spurious warning
/* If this is a gagged instantiation, gag errors.
* Future optimisation: If the results are actually needed, errors
* would already be gagged, so we don't really need to run semantic
* on the members.
*/
if (needGagging)
oldGaggedErrors = global.startGagging();
for (size_t i = 0; i < tempinst.members.dim; i++)
{
Dsymbol s = (*tempinst.members)[i];
s.semantic3(sc);
if (tempinst.gagged && global.errors != olderrors)
break;
}
if (global.errors != olderrors)
{
if (!tempinst.errors)
{
if (!tempdecl.literal)
tempinst.error(tempinst.loc, "error instantiating");
if (tempinst.tinst)
tempinst.tinst.printInstantiationTrace();
}
tempinst.errors = true;
}
if (needGagging)
global.endGagging(oldGaggedErrors);
sc = sc.pop();
sc.pop();
}
override void visit(TemplateMixin tmix)
{
if (tmix.semanticRun >= PASS.semantic3)
return;
tmix.semanticRun = PASS.semantic3;
static if (LOG)
{
printf("TemplateMixin.semantic3('%s')\n", tmix.toChars());
}
if (!tmix.members)
return;
sc = sc.push(tmix.argsym);
sc = sc.push(tmix);
for (size_t i = 0; i < tmix.members.dim; i++)
{
Dsymbol s = (*tmix.members)[i];
s.semantic3(sc);
}
sc = sc.pop();
sc.pop();
}
override void visit(Module mod)
{
//printf("Module::semantic3('%s'): parent = %p\n", toChars(), parent);
if (mod.semanticRun != PASS.semantic2done)
return;
mod.semanticRun = PASS.semantic3;
// Note that modules get their own scope, from scratch.
// This is so regardless of where in the syntax a module
// gets imported, it is unaffected by context.
Scope* sc = Scope.createGlobal(mod); // create root scope
//printf("Module = %p\n", sc.scopesym);
// Pass 3 semantic routines: do initializers and function bodies
for (size_t i = 0; i < mod.members.dim; i++)
{
Dsymbol s = (*mod.members)[i];
//printf("Module %s: %s.semantic3()\n", toChars(), s.toChars());
s.semantic3(sc);
mod.runDeferredSemantic2();
}
if (mod.userAttribDecl)
{
mod.userAttribDecl.semantic3(sc);
}
sc = sc.pop();
sc.pop();
mod.semanticRun = PASS.semantic3done;
}
override void visit(FuncDeclaration funcdecl)
{
//printf("FuncDeclaration::semantic3(%s '%s', sc = %p)\n", funcdecl.kind(), funcdecl.toChars(), sc);
/* Determine if function should add `return 0;`
*/
bool addReturn0()
{
//printf("addReturn0()\n");
auto f = funcdecl.type.isTypeFunction();
// C11 5.1.2.2.3
if (sc.flags & SCOPE.Cfile && funcdecl.isCMain() && f.next.ty == Tint32)
return true;
return f.next.ty == Tvoid &&
(funcdecl.isMain() || global.params.betterC && funcdecl.isCMain());
}
VarDeclaration _arguments = null;
if (!funcdecl.parent)
{
if (global.errors)
return;
//printf("FuncDeclaration::semantic3(%s '%s', sc = %p)\n", kind(), toChars(), sc);
assert(0);
}
if (funcdecl.errors || isError(funcdecl.parent))
{
funcdecl.errors = true;
// Mark that the return type could not be inferred
if (funcdecl.inferRetType)
{
assert(funcdecl.type);
auto tf = funcdecl.type.isTypeFunction();
// Only change the return type s.t. other analysis is
// still possible e.g. missmatched parameter types
if (tf && !tf.next)
tf.next = Type.terror;
}
return;
}
//printf("FuncDeclaration::semantic3('%s.%s', %p, sc = %p, loc = %s)\n", funcdecl.parent.toChars(), funcdecl.toChars(), funcdecl, sc, funcdecl.loc.toChars());
//fflush(stdout);
//printf("storage class = x%x %x\n", sc.stc, storage_class);
//{ static int x; if (++x == 2) *(char*)0=0; }
//printf("\tlinkage = %d\n", sc.linkage);
if (funcdecl.ident == Id.assign && !funcdecl.inuse)
{
if (funcdecl.storage_class & STC.inference)
{
/* https://issues.dlang.org/show_bug.cgi?id=15044
* For generated opAssign function, any errors
* from its body need to be gagged.
*/
uint oldErrors = global.startGagging();
++funcdecl.inuse;
funcdecl.semantic3(sc);
--funcdecl.inuse;
if (global.endGagging(oldErrors)) // if errors happened
{
// Disable generated opAssign, because some members forbid identity assignment.
funcdecl.storage_class |= STC.disable;
funcdecl.fbody = null; // remove fbody which contains the error
funcdecl.semantic3Errors = false;
}
return;
}
}
//printf(" sc.incontract = %d\n", (sc.flags & SCOPE.contract));
if (funcdecl.semanticRun >= PASS.semantic3)
return;
funcdecl.semanticRun = PASS.semantic3;
funcdecl.semantic3Errors = false;
if (!funcdecl.type || funcdecl.type.ty != Tfunction)
return;
TypeFunction f = cast(TypeFunction)funcdecl.type;
if (!funcdecl.inferRetType && f.next.ty == Terror)
return;
if (!funcdecl.fbody && funcdecl.inferRetType && !f.next)
{
funcdecl.error("has no function body with return type inference");
return;
}
uint oldErrors = global.errors;
auto fds = FuncDeclSem3(funcdecl,sc);
fds.checkInContractOverrides();
// Remember whether we need to generate an 'out' contract.
immutable bool needEnsure = FuncDeclaration.needsFensure(funcdecl);
if (funcdecl.fbody || funcdecl.frequires || needEnsure)
{
/* Symbol table into which we place parameters and nested functions,
* solely to diagnose name collisions.
*/
funcdecl.localsymtab = new DsymbolTable();
// Establish function scope
auto ss = new ScopeDsymbol(funcdecl.loc, null);
// find enclosing scope symbol, might skip symbol-less CTFE and/or FuncExp scopes
ss.parent = sc.inner().scopesym;
ss.endlinnum = funcdecl.endloc.linnum;
Scope* sc2 = sc.push(ss);
sc2.func = funcdecl;
sc2.parent = funcdecl;
sc2.ctorflow.callSuper = CSX.none;
sc2.sbreak = null;
sc2.scontinue = null;
sc2.sw = null;
sc2.fes = funcdecl.fes;
sc2.linkage = LINK.d;
sc2.stc &= STC.flowThruFunction;
sc2.visibility = Visibility(Visibility.Kind.public_);
sc2.explicitVisibility = 0;
sc2.aligndecl = null;
if (funcdecl.ident != Id.require && funcdecl.ident != Id.ensure)
sc2.flags = sc.flags & ~SCOPE.contract;
sc2.flags &= ~SCOPE.compile;
sc2.tf = null;
sc2.os = null;
sc2.inLoop = false;
sc2.userAttribDecl = null;
if (sc2.intypeof == 1)
sc2.intypeof = 2;
sc2.ctorflow.fieldinit = null;
/* Note: When a lambda is defined immediately under aggregate member
* scope, it should be contextless due to prevent interior pointers.
* e.g.
* // dg points 'this' - its interior pointer
* class C { int x; void delegate() dg = (){ this.x = 1; }; }
*
* However, lambdas could be used inside typeof, in order to check
* some expressions validity at compile time. For such case the lambda
* body can access aggregate instance members.
* e.g.
* class C { int x; static assert(is(typeof({ this.x = 1; }))); }
*
* To properly accept it, mark these lambdas as member functions.
*/
if (auto fld = funcdecl.isFuncLiteralDeclaration())
{
if (auto ad = funcdecl.isMember2())
{
if (!sc.intypeof)
{
if (fld.tok == TOK.delegate_)
funcdecl.error("cannot be %s members", ad.kind());
else
fld.tok = TOK.function_;
}
else
{
if (fld.tok != TOK.function_)
fld.tok = TOK.delegate_;
}
}
}
funcdecl.declareThis(sc2);
// Reverts: https://issues.dlang.org/show_bug.cgi?id=5710
// No compiler supports this, and there was never any spec for it.
if (funcdecl.isThis2)
{
funcdecl.deprecation("function requires a dual-context, which is deprecated");
if (auto ti = sc2.parent ? sc2.parent.isInstantiated() : null)
ti.printInstantiationTrace(Classification.deprecation);
}
//printf("[%s] ad = %p vthis = %p\n", loc.toChars(), ad, vthis);
//if (vthis) printf("\tvthis.type = %s\n", vthis.type.toChars());
// Declare hidden variable _arguments[] and _argptr
if (f.parameterList.varargs == VarArg.variadic)
{
if (f.linkage == LINK.d)
{
// Variadic arguments depend on Typeinfo being defined.
if (!global.params.useTypeInfo || !Type.dtypeinfo || !Type.typeinfotypelist)
{
if (!global.params.useTypeInfo)
funcdecl.error("D-style variadic functions cannot be used with -betterC");
else if (!Type.typeinfotypelist)
funcdecl.error("`object.TypeInfo_Tuple` could not be found, but is implicitly used in D-style variadic functions");
else
funcdecl.error("`object.TypeInfo` could not be found, but is implicitly used in D-style variadic functions");
fatal();
}
// Declare _arguments[]
funcdecl.v_arguments = new VarDeclaration(funcdecl.loc, Type.typeinfotypelist.type, Id._arguments_typeinfo, null);
funcdecl.v_arguments.storage_class |= STC.temp | STC.parameter;
funcdecl.v_arguments.dsymbolSemantic(sc2);
sc2.insert(funcdecl.v_arguments);
funcdecl.v_arguments.parent = funcdecl;
//Type t = Type.dtypeinfo.type.constOf().arrayOf();
Type t = Type.dtypeinfo.type.arrayOf();
_arguments = new VarDeclaration(funcdecl.loc, t, Id._arguments, null);
_arguments.storage_class |= STC.temp;
_arguments.dsymbolSemantic(sc2);
sc2.insert(_arguments);
_arguments.parent = funcdecl;
}
if (f.linkage == LINK.d || f.parameterList.length)
{
// Declare _argptr
Type t = target.va_listType(funcdecl.loc, sc);
// Init is handled in FuncDeclaration_toObjFile
funcdecl.v_argptr = new VarDeclaration(funcdecl.loc, t, Id._argptr, new VoidInitializer(funcdecl.loc));
funcdecl.v_argptr.storage_class |= STC.temp;
funcdecl.v_argptr.dsymbolSemantic(sc2);
sc2.insert(funcdecl.v_argptr);
funcdecl.v_argptr.parent = funcdecl;
}
}
/* Declare all the function parameters as variables
* and install them in parameters[]
*/
if (const nparams = f.parameterList.length)
{
/* parameters[] has all the tuples removed, as the back end
* doesn't know about tuples
*/
funcdecl.parameters = new VarDeclarations();
funcdecl.parameters.reserve(nparams);
foreach (i, fparam; f.parameterList)
{
Identifier id = fparam.ident;
StorageClass stc = 0;
if (!id)
{
/* Generate identifier for un-named parameter,
* because we need it later on.
*/
fparam.ident = id = Identifier.generateId("_param_", i);
stc |= STC.temp;
}
Type vtype = fparam.type;
auto v = new VarDeclaration(funcdecl.loc, vtype, id, null);
//printf("declaring parameter %s of type %s\n", v.toChars(), v.type.toChars());
stc |= STC.parameter;
if (f.parameterList.varargs == VarArg.typesafe && i + 1 == nparams)
{
stc |= STC.variadic;
auto vtypeb = vtype.toBasetype();
if (vtypeb.ty == Tarray)
{
/* Since it'll be pointing into the stack for the array
* contents, it needs to be `scope`
*/
stc |= STC.scope_;
}
}
if ((funcdecl.flags & FUNCFLAG.inferScope) && !(fparam.storageClass & STC.scope_))
stc |= STC.maybescope;
stc |= fparam.storageClass & (STC.IOR | STC.return_ | STC.scope_ | STC.lazy_ | STC.final_ | STC.TYPECTOR | STC.nodtor | STC.returnScope);
v.storage_class = stc;
v.dsymbolSemantic(sc2);
if (!sc2.insert(v))
{
funcdecl.error("parameter `%s.%s` is already defined", funcdecl.toChars(), v.toChars());
funcdecl.errors = true;
}
else
funcdecl.parameters.push(v);
funcdecl.localsymtab.insert(v);
v.parent = funcdecl;
if (fparam.userAttribDecl)
v.userAttribDecl = fparam.userAttribDecl;
}
}
// Declare the tuple symbols and put them in the symbol table,
// but not in parameters[].
if (f.parameterList.parameters)
foreach (fparam; *f.parameterList.parameters)
{
if (!fparam.ident)
continue; // never used, so ignore
// expand any tuples
if (fparam.type.ty != Ttuple)
continue;
TypeTuple t = cast(TypeTuple)fparam.type;
size_t dim = Parameter.dim(t.arguments);
auto exps = new Objects(dim);
foreach (j; 0 .. dim)
{
Parameter narg = Parameter.getNth(t.arguments, j);
assert(narg.ident);
VarDeclaration v = sc2.search(Loc.initial, narg.ident, null).isVarDeclaration();
assert(v);
(*exps)[j] = new VarExp(v.loc, v);
}
assert(fparam.ident);
auto v = new TupleDeclaration(funcdecl.loc, fparam.ident, exps);
//printf("declaring tuple %s\n", v.toChars());
v.isexp = true;
if (!sc2.insert(v))
funcdecl.error("parameter `%s.%s` is already defined", funcdecl.toChars(), v.toChars());
funcdecl.localsymtab.insert(v);
v.parent = funcdecl;
}
// Precondition invariant
Statement fpreinv = null;
if (funcdecl.addPreInvariant())
{
Expression e = addInvariant(funcdecl.isThis(), funcdecl.vthis);
if (e)
fpreinv = new ExpStatement(Loc.initial, e);
}
// Postcondition invariant
Statement fpostinv = null;
if (funcdecl.addPostInvariant())
{
Expression e = addInvariant(funcdecl.isThis(), funcdecl.vthis);
if (e)
fpostinv = new ExpStatement(Loc.initial, e);
}
// Pre/Postcondition contract
if (!funcdecl.fbody)
funcdecl.buildEnsureRequire();
Scope* scout = null;
if (needEnsure || funcdecl.addPostInvariant())
{
/* https://issues.dlang.org/show_bug.cgi?id=3657
* Set the correct end line number for fensure scope.
*/
uint fensure_endlin = funcdecl.endloc.linnum;
if (funcdecl.fensure)
if (auto s = funcdecl.fensure.isScopeStatement())
fensure_endlin = s.endloc.linnum;
if ((needEnsure && global.params.useOut == CHECKENABLE.on) || fpostinv)
{
funcdecl.returnLabel = funcdecl.searchLabel(Id.returnLabel);
}
// scope of out contract (need for vresult.semantic)
auto sym = new ScopeDsymbol(funcdecl.loc, null);
sym.parent = sc2.scopesym;
sym.endlinnum = fensure_endlin;
scout = sc2.push(sym);
}
if (funcdecl.fbody)
{
auto sym = new ScopeDsymbol(funcdecl.loc, null);
sym.parent = sc2.scopesym;
sym.endlinnum = funcdecl.endloc.linnum;
sc2 = sc2.push(sym);
auto ad2 = funcdecl.isMemberLocal();
/* If this is a class constructor
*/
if (ad2 && funcdecl.isCtorDeclaration())
{
sc2.ctorflow.allocFieldinit(ad2.fields.dim);
foreach (v; ad2.fields)
{
v.ctorinit = 0;
}
}
bool inferRef = (f.isref && (funcdecl.storage_class & STC.auto_));
funcdecl.fbody = funcdecl.fbody.statementSemantic(sc2);
if (!funcdecl.fbody)
funcdecl.fbody = new CompoundStatement(Loc.initial, new Statements());
if (funcdecl.naked)
{
fpreinv = null; // can't accommodate with no stack frame
fpostinv = null;
}
assert(funcdecl.type == f || (funcdecl.type.ty == Tfunction && f.purity == PURE.impure && (cast(TypeFunction)funcdecl.type).purity >= PURE.fwdref));
f = cast(TypeFunction)funcdecl.type;
if (funcdecl.inferRetType)
{
// If no return type inferred yet, then infer a void
if (!f.next)
f.next = Type.tvoid;
if (f.checkRetType(funcdecl.loc))
funcdecl.fbody = new ErrorStatement();
else if (funcdecl.isMain())
funcdecl.checkDmain(); // Check main() parameters and return type
}
if (global.params.vcomplex && f.next !is null)
f.next.checkComplexTransition(funcdecl.loc, sc);
if (funcdecl.returns && !funcdecl.fbody.isErrorStatement())
{
for (size_t i = 0; i < funcdecl.returns.dim;)
{
Expression exp = (*funcdecl.returns)[i].exp;
if (exp.op == EXP.variable && (cast(VarExp)exp).var == funcdecl.vresult)
{
if (addReturn0())
exp.type = Type.tint32;
else
exp.type = f.next;
// Remove `return vresult;` from returns
funcdecl.returns.remove(i);
continue;
}
if (inferRef && f.isref && !exp.type.constConv(f.next)) // https://issues.dlang.org/show_bug.cgi?id=13336
f.isref = false;
i++;
}
}
if (f.isref) // Function returns a reference
{
if (funcdecl.storage_class & STC.auto_)
funcdecl.storage_class &= ~STC.auto_;
}
// handle NRVO
if (!target.isReturnOnStack(f, funcdecl.needThis()) || !funcdecl.checkNRVO())
funcdecl.nrvo_can = 0;
if (funcdecl.fbody.isErrorStatement())
{
}
else if (funcdecl.isStaticCtorDeclaration())
{
/* It's a static constructor. Ensure that all
* ctor consts were initialized.
*/
ScopeDsymbol pd = funcdecl.toParent().isScopeDsymbol();
for (size_t i = 0; i < pd.members.dim; i++)
{
Dsymbol s = (*pd.members)[i];
s.checkCtorConstInit();
}
}
else if (ad2 && funcdecl.isCtorDeclaration())
{
ClassDeclaration cd = ad2.isClassDeclaration();
// Verify that all the ctorinit fields got initialized
if (!(sc2.ctorflow.callSuper & CSX.this_ctor))
{
foreach (i, v; ad2.fields)
{
if (v.isThisDeclaration())
continue;
if (v.ctorinit == 0)
{
/* Current bugs in the flow analysis:
* 1. union members should not produce error messages even if
* not assigned to
* 2. structs should recognize delegating opAssign calls as well
* as delegating calls to other constructors
*/
if (v.isCtorinit() && !v.type.isMutable() && cd)
funcdecl.error("missing initializer for %s field `%s`", MODtoChars(v.type.mod), v.toChars());
else if (v.storage_class & STC.nodefaultctor)
error(funcdecl.loc, "field `%s` must be initialized in constructor", v.toChars());
else if (v.type.needsNested())
error(funcdecl.loc, "field `%s` must be initialized in constructor, because it is nested struct", v.toChars());
}
else
{
bool mustInit = (v.storage_class & STC.nodefaultctor || v.type.needsNested());
if (mustInit && !(sc2.ctorflow.fieldinit[i].csx & CSX.this_ctor))
{
funcdecl.error("field `%s` must be initialized but skipped", v.toChars());
}
}
}
}
sc2.ctorflow.freeFieldinit();
if (cd && !(sc2.ctorflow.callSuper & CSX.any_ctor) && cd.baseClass && cd.baseClass.ctor)
{
sc2.ctorflow.callSuper = CSX.none;
// Insert implicit super() at start of fbody
Type tthis = ad2.type.addMod(funcdecl.vthis.type.mod);
FuncDeclaration fd = resolveFuncCall(Loc.initial, sc2, cd.baseClass.ctor, null, tthis, null, FuncResolveFlag.quiet);
if (!fd)
{
funcdecl.error("no match for implicit `super()` call in constructor");
}
else if (fd.storage_class & STC.disable)
{
funcdecl.error("cannot call `super()` implicitly because it is annotated with `@disable`");
}
else
{
Expression e1 = new SuperExp(Loc.initial);
Expression e = new CallExp(Loc.initial, e1);
e = e.expressionSemantic(sc2);
Statement s = new ExpStatement(Loc.initial, e);
funcdecl.fbody = new CompoundStatement(Loc.initial, s, funcdecl.fbody);
}
}
//printf("ctorflow.callSuper = x%x\n", sc2.ctorflow.callSuper);
}
/* https://issues.dlang.org/show_bug.cgi?id=17502
* Wait until after the return type has been inferred before
* generating the contracts for this function, and merging contracts
* from overrides.
*
* https://issues.dlang.org/show_bug.cgi?id=17893
* However should take care to generate this before inferered
* function attributes are applied, such as 'nothrow'.
*
* This was originally at the end of the first semantic pass, but
* required a fix-up to be done here for the '__result' variable
* type of __ensure() inside auto functions, but this didn't work
* if the out parameter was implicit.
*/
funcdecl.buildEnsureRequire();
// Check for errors related to 'nothrow'.
const blockexit = funcdecl.fbody.blockExit(funcdecl, f.isnothrow);
if (f.isnothrow && blockexit & BE.throw_)
error(funcdecl.loc, "`nothrow` %s `%s` may throw", funcdecl.kind(), funcdecl.toPrettyChars());
if (!(blockexit & (BE.throw_ | BE.halt) || funcdecl.flags & FUNCFLAG.hasCatches))
{
/* Don't generate unwind tables for this function
* https://issues.dlang.org/show_bug.cgi?id=17997
*/
funcdecl.eh_none = true;
}
if (funcdecl.flags & FUNCFLAG.nothrowInprocess)
{
if (funcdecl.type == f)
f = cast(TypeFunction)f.copy();
f.isnothrow = !(blockexit & BE.throw_);
}
if (funcdecl.fbody.isErrorStatement())
{
}
else if (ad2 && funcdecl.isCtorDeclaration())
{
/* Append:
* return this;
* to function body
*/
if (blockexit & BE.fallthru)
{
Statement s = new ReturnStatement(funcdecl.loc, null);
s = s.statementSemantic(sc2);
funcdecl.fbody = new CompoundStatement(funcdecl.loc, funcdecl.fbody, s);
funcdecl.hasReturnExp |= (funcdecl.hasReturnExp & 1 ? 16 : 1);
}
}
else if (funcdecl.fes)
{
// For foreach(){} body, append a return 0;
if (blockexit & BE.fallthru)
{
Expression e = IntegerExp.literal!0;
Statement s = new ReturnStatement(Loc.initial, e);
funcdecl.fbody = new CompoundStatement(Loc.initial, funcdecl.fbody, s);
funcdecl.hasReturnExp |= (funcdecl.hasReturnExp & 1 ? 16 : 1);
}
assert(!funcdecl.returnLabel);
}
else if (f.next.toBasetype().ty == Tnoreturn)
{
// Fallthrough despite being declared as noreturn? return is already rejected when evaluating the ReturnStatement
if (blockexit & BE.fallthru)
{
funcdecl.error("is typed as `%s` but does return", f.next.toChars());
funcdecl.loc.errorSupplemental("`noreturn` functions must either throw, abort or loop indefinitely");
}
}
else
{
const(bool) inlineAsm = (funcdecl.hasReturnExp & 8) != 0;
if ((blockexit & BE.fallthru) && f.next.ty != Tvoid && !inlineAsm && !(sc.flags & SCOPE.Cfile))
{
if (!funcdecl.hasReturnExp)
funcdecl.error("has no `return` statement, but is expected to return a value of type `%s`", f.next.toChars());
else
funcdecl.error("no `return exp;` or `assert(0);` at end of function");
}
}
if (funcdecl.returns)
{
bool implicit0 = addReturn0();
Type tret = implicit0 ? Type.tint32 : f.next;
assert(tret.ty != Tvoid);
if (funcdecl.vresult || funcdecl.returnLabel)
funcdecl.buildResultVar(scout ? scout : sc2, tret);
/* Cannot move this loop into NrvoWalker, because
* returns[i] may be in the nested delegate for foreach-body.
*/
for (size_t i = 0; i < funcdecl.returns.dim; i++)
{
ReturnStatement rs = (*funcdecl.returns)[i];
Expression exp = rs.exp;
if (exp.op == EXP.error)
continue;
if (tret.ty == Terror)
{
// https://issues.dlang.org/show_bug.cgi?id=13702
exp = checkGC(sc2, exp);
continue;
}
/* If the expression in the return statement (exp) cannot be implicitly
* converted to the return type (tret) of the function and if the
* type of the expression is type isolated, then it may be possible
* that a promotion to `immutable` or `inout` (through a cast) will
* match the return type.
*/
if (!exp.implicitConvTo(tret) && funcdecl.isTypeIsolated(exp.type))
{
/* https://issues.dlang.org/show_bug.cgi?id=20073
*
* The problem is that if the type of the returned expression (exp.type)
* is an aggregated declaration with an alias this, the alias this may be
* used for the conversion testing without it being an isolated type.
*
* To make sure this does not happen, we can test here the implicit conversion
* only for the aggregated declaration type by using `implicitConvToWithoutAliasThis`.
* The implicit conversion with alias this is taken care of later.
*/
AggregateDeclaration aggDecl = isAggregate(exp.type);
TypeStruct tstruct;
TypeClass tclass;
bool hasAliasThis;
if (aggDecl && aggDecl.aliasthis)
{
hasAliasThis = true;
tclass = exp.type.isTypeClass();
if (!tclass)
tstruct = exp.type.isTypeStruct();
assert(tclass || tstruct);
}
if (hasAliasThis)
{
if (tclass)
{
if ((cast(TypeClass)(exp.type.immutableOf())).implicitConvToWithoutAliasThis(tret))
exp = exp.castTo(sc2, exp.type.immutableOf());
else if ((cast(TypeClass)(exp.type.wildOf())).implicitConvToWithoutAliasThis(tret))
exp = exp.castTo(sc2, exp.type.wildOf());
}
else
{
if ((cast(TypeStruct)exp.type.immutableOf()).implicitConvToWithoutAliasThis(tret))
exp = exp.castTo(sc2, exp.type.immutableOf());
else if ((cast(TypeStruct)exp.type.immutableOf()).implicitConvToWithoutAliasThis(tret))
exp = exp.castTo(sc2, exp.type.wildOf());
}
}
else
{
if (exp.type.immutableOf().implicitConvTo(tret))
exp = exp.castTo(sc2, exp.type.immutableOf());
else if (exp.type.wildOf().implicitConvTo(tret))
exp = exp.castTo(sc2, exp.type.wildOf());
}
}
const hasCopyCtor = exp.type.ty == Tstruct && (cast(TypeStruct)exp.type).sym.hasCopyCtor;
// if a copy constructor is present, the return type conversion will be handled by it
if (!(hasCopyCtor && exp.isLvalue()))
{
if (f.isref && !MODimplicitConv(exp.type.mod, tret.mod) && !tret.isTypeSArray())
error(exp.loc, "expression `%s` of type `%s` is not implicitly convertible to return type `ref %s`",
exp.toChars(), exp.type.toChars(), tret.toChars());
else
exp = exp.implicitCastTo(sc2, tret);
}
if (f.isref)
{
// Function returns a reference
exp = exp.toLvalue(sc2, exp);
checkReturnEscapeRef(sc2, exp, false);
exp = exp.optimize(WANTvalue, /*keepLvalue*/ true);
}
else
{
exp = exp.optimize(WANTvalue);
/* https://issues.dlang.org/show_bug.cgi?id=10789
* If NRVO is not possible, all returned lvalues should call their postblits.
*/
if (!funcdecl.nrvo_can)
exp = doCopyOrMove(sc2, exp, f.next);
if (tret.hasPointers())
checkReturnEscape(sc2, exp, false);
}
exp = checkGC(sc2, exp);
if (funcdecl.vresult)
{
// Create: return vresult = exp;
exp = new BlitExp(rs.loc, funcdecl.vresult, exp);
exp.type = funcdecl.vresult.type;
if (rs.caseDim)
exp = Expression.combine(exp, new IntegerExp(rs.caseDim));
}
else if (funcdecl.tintro && !tret.equals(funcdecl.tintro.nextOf()))
{
exp = exp.implicitCastTo(sc2, funcdecl.tintro.nextOf());
}
rs.exp = exp;
}
}
if (funcdecl.nrvo_var || funcdecl.returnLabel)
{
scope NrvoWalker nw = new NrvoWalker();
nw.fd = funcdecl;
nw.sc = sc2;
nw.visitStmt(funcdecl.fbody);
}
sc2 = sc2.pop();
}
if (global.params.inclusiveInContracts)
{
funcdecl.frequire = funcdecl.mergeFrequireInclusivePreview(
funcdecl.frequire, funcdecl.fdrequireParams);
}
else
{
funcdecl.frequire = funcdecl.mergeFrequire(funcdecl.frequire, funcdecl.fdrequireParams);
}
funcdecl.fensure = funcdecl.mergeFensure(funcdecl.fensure, Id.result, funcdecl.fdensureParams);
Statement freq = funcdecl.frequire;
Statement fens = funcdecl.fensure;
/* Do the semantic analysis on the [in] preconditions and
* [out] postconditions.
*/
if (freq)
{
/* frequire is composed of the [in] contracts
*/
auto sym = new ScopeDsymbol(funcdecl.loc, null);
sym.parent = sc2.scopesym;
sym.endlinnum = funcdecl.endloc.linnum;
sc2 = sc2.push(sym);
sc2.flags = (sc2.flags & ~SCOPE.contract) | SCOPE.require;
// BUG: need to error if accessing out parameters
// BUG: need to disallow returns and throws
// BUG: verify that all in and ref parameters are read
freq = freq.statementSemantic(sc2);
freq.blockExit(funcdecl, false);
funcdecl.eh_none = false;
sc2 = sc2.pop();
if (global.params.useIn == CHECKENABLE.off)
freq = null;
}
if (fens)
{
/* fensure is composed of the [out] contracts
*/