Bug 20934 – preview=dtorfields segfaults for disabled/extern constructors

This code segfaults when compiled with -preview=dtorfields: ========================= struct Array { ~this() {} } struct CyclicArray() { Array array; @disable this(); } auto heapArray = CyclicArray!()(); ========================= dmd -c -o- cyclic_array.d cyclic_array.d(12): Error: constructor cyclic_array.CyclicArray!().CyclicArray.this cannot be used because it is annotated with @disable cyclic_array.d(12): Error: this cannot be interpreted at compile time, because it has no available source code dmd -c -o- preview=dtorfields cyclic_array.d Segmentation fault (core dumped) Running in gdb shows that it tries to do semantic analysis on the missing body of CyclicArrays disabled dtor: gdb generated/linux/debug/64/dmd -batch -ex "run -c -o- -preview=dtorfields cyclic_array.d" -ex "bt" &> gdb.log [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0x0000000008182b6c in Statement::isCompoundStatement() (this=0x0) at src/dmd/statement.d:424 424 inout(CompoundStatement) isCompoundStatement() { return stmt == STMT.Compound ? cast(typeof(return))this : null; } #0 0x0000000008182b6c in Statement::isCompoundStatement() (this=0x0) at src/dmd/statement.d:424 #1 0x00000000081c0b29 in _D3dmd12statementsem15semanticNoScopeFCQBl9statement9StatementPSQCk6dscope5ScopeZQBr (s=0x0, sc=0x7ffffddea4b0) at src/dmd/statementsem.d:4318 #2 0x00000000081c0397 in _D3dmd12statementsem13semanticScopeFCQBj9statement9StatementPSQCi6dscope5ScopeQBqQBtZQBx (s=0x0, sc=0x7ffffdde98b0, sbreak=0x0, scontinue=0x0) at src/dmd/statementsem.d:4336 #3 0x00000000081daa78 in StatementSemanticVisitor::visit(TryCatchStatement*) (this=0x7ffffffe90d0, tcs=0x7ffffdde9ef0) at src/dmd/statementsem.d:3826 #4 0x00000000081ec243 in TryCatchStatement::accept(Visitor*) (this=0x7ffffdde9ef0, v=0x7ffffffe90d0) at src/dmd/statement.d:1980 #5 0x0000000008131bf3 in statementSemantic(Statement*, Scope*) (s=0x7ffffdde9ef0, sc=0x7ffffdde98b0) at src/dmd/statementsem.d:127 #6 0x00000000081f0fae in Semantic3Visitor::visit(FuncDeclaration*) (this=0x7ffffffea368, funcdecl=0x7ffffdde7750) at src/dmd/semantic3.d:577 #7 0x00000000081faeee in Semantic3Visitor::visit(CtorDeclaration*) (this=0x7ffffffea368, ctor=0x7ffffdde7750) at src/dmd/semantic3.d:1407 #8 0x00000000082a3563 in CtorDeclaration::accept(Visitor*) (this=0x7ffffdde7750, v=0x7ffffffea368) at src/dmd/func.d:3545 #9 0x000000000819131b in semantic3(Dsymbol*, Scope*) (dsym=0x7ffffdde7750, sc=0x7ffffdde80d0) at src/dmd/semantic3.d:81 #10 0x0000000008286706 in FuncDeclaration::functionSemantic3() (this=0x7ffffdde7750) at src/dmd/func.d:455 #11 0x000000000816cd46 in FuncDeclaration::functionSemantic() (this=0x7ffffdde7750) at src/dmd/func.d:429 #12 0x00000000082cdde2 in ExpressionSemanticVisitor::visit(DotVarExp*) (this=0x7ffffffea6a0, exp=0x7ffffdde9b00) at src/dmd/expressionsem.d:6212 #13 0x00000000082f5ce3 in DotVarExp::accept(Visitor*) (this=0x7ffffdde9b00, v=0x7ffffffea6a0) at src/dmd/expression.d:4713 #14 0x00000000081313d3 in expressionSemantic(Expression*, Scope*) (e=0x7ffffdde9b00, sc=0x7fffff6b7d40) at src/dmd/expressionsem.d:11391 #15 0x00000000082c5a21 in _D3dmd13expressionsem11unaSemanticFCQBi10expression6UnaExpPSQCg6dscope5ScopeZCQCyQBq10Expression (e=0x7ffffdde9b50, sc=0x7fffff6b7d40) at src/dmd/expressionsem.d:11337 #16 0x00000000082c0699 in ExpressionSemanticVisitor::visit(CallExp*) (this=0x7ffffffeb760, exp=0x7ffffdde9b50) at src/dmd/expressionsem.d:4311 #17 0x00000000082f5f03 in CallExp::accept(Visitor*) (this=0x7ffffdde9b50, v=0x7ffffffeb760) at src/dmd/expression.d:4970 #18 0x00000000081313d3 in expressionSemantic(Expression*, Scope*) (e=0x7ffffdde9b50, sc=0x7fffff6b7d40) at src/dmd/expressionsem.d:11391 #19 0x00000000082c13fe in ExpressionSemanticVisitor::visit(CallExp*) (this=0x7ffffffec7f0, exp=0x7fffff6b7960) at src/dmd/expressionsem.d:4437 #20 0x00000000082f5f03 in CallExp::accept(Visitor*) (this=0x7fffff6b7960, v=0x7ffffffec7f0) at src/dmd/expression.d:4970 #21 0x00000000081313d3 in expressionSemantic(Expression*, Scope*) (e=0x7fffff6b7960, sc=0x7fffff6b7d40) at src/dmd/expressionsem.d:11391 #22 0x000000000828eff1 in _D3dmd7initsem9inferTypeFCQy4init11InitializerPSQBu6dscope5ScopeZ8visitExpMFCQCxQCa14ExpInitializerZQCx (init=0x7fffff6b79e0) at src/dmd/initsem.d:644 #23 0x000000000828e82c in _D3dmd7initsem9inferTypeFCQy4init11InitializerPSQBu6dscope5ScopeZQBo (init=0x7fffff6b79e0, sc=0x7fffff6b7d40) at src/dmd/initsem.d:702 #24 0x0000000008324dc8 in DsymbolSemanticVisitor::visit(VarDeclaration*) (this=0x7ffffffed308, dsym=0x7fffff6b7a10) at src/dmd/dsymbolsem.d:822 #25 0x000000000838efe3 in VarDeclaration::accept(Visitor*) (this=0x7fffff6b7a10, v=0x7ffffffed308) at src/dmd/declaration.d:1646 #26 0x000000000818d68b in dsymbolSemantic(Dsymbol*, Scope*) (dsym=0x7fffff6b7a10, sc=0x7fffff6b7d40) at src/dmd/dsymbolsem.d:564 #27 0x000000000832cc73 in _D3dmd10dsymbolsem22DsymbolSemanticVisitor5visitMRCQBx7dmodule6ModuleZ__T9__lambda2TCQDf7dsymbol7DsymbolZQBgMFQBaZv (s=0x7fffff6b7a10) at src/dmd/dsymbolsem.d:2258 #28 0x000000000812d7d0 in _D3dmd7dsymbol14foreachDsymbolFPSQBf4root5array__T5ArrayTCQCeQCd7DsymbolZQxMDFQvZvZv (symbols=0x7fffff6b6570, dg=...) at src/dmd/dsymbol.d:98 #29 0x000000000832cbd4 in DsymbolSemanticVisitor::visit(Module*) (this=0x7ffffffed438, m=0x7fffff6b5300) at src/dmd/dsymbolsem.d:2255 #30 0x000000000827abb3 in Module::accept(Visitor*) (this=0x7fffff6b5300, v=0x7ffffffed438) at src/dmd/dmodule.d:1464 #31 0x000000000818d68b in dsymbolSemantic(Dsymbol*, Scope*) (dsym=0x7fffff6b5300, sc=0x0) at src/dmd/dsymbolsem.d:564 #32 0x0000000008258076 in _D3dmd4mars7tryMainFmPPxaKSQz7globals5ParamZi (argc=5, argv=0x7ffffffee008, params=...) at src/dmd/mars.d:564 #33 0x00000000082641a2 in D main (_param_0=...) at src/dmd/mars.d:950

Templates are unnecessary, it's only required to contain a body-less constructor declaration

dlang/dmd pull request #11658 "Fix 20934 - preview=dtorfields segfaults for disabled/extern construc…" was merged into master: - d856a146c4c7ea67e387928c08589b3be288ef27 by MoonlightSentinel: Fix 20934 - preview=dtorfields segfaults for disabled/extern constructors Don't try to insert a destructor body if there's no body because the following semantic would segfault due to the missing try-block https://github.com/dlang/dmd/pull/11658