https://issues.dlang.org/show_bug.cgi?id=18670

          Issue ID: 18670
           Summary: compiler segfault if `new` on a union type with
                    dip1000
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: john.loughran.colvin@gmail.com

Found while trying to compile Adam D. Ruppe's terminal-emulator, reduced with dustmite and some manual work

% cat terminalemulator.d
void foo() {
        new OVERLAPPED;
}

union OVERLAPPED {
        uint     OffsetHigh;
        uint     Pointer;
}
% gdb dmd
< ... blah blah ... >
(gdb) r terminalemulator.d -dip1000
< ... blah blah ... >
DMD v2.079.0-283-g2e21d0713-dirty DEBUG

Program received signal SIGSEGV, Segmentation fault.
0x000000000059f2bd in dmd.escape.escapeByValue(dmd.expression.Expression,
dmd.escape.EscapeByResults*) (er=0x7ffffffeca60, e=0x0) at dmd/escape.d:1293
1293        e.accept(v);
(gdb) bt
#0  0x000000000059f2bd in dmd.escape.escapeByValue(dmd.expression.Expression,
dmd.escape.EscapeByResults*) (er=0x7ffffffeca60, e=0x0) at dmd/escape.d:1293
#1  0x000000000059e4a9 in dmd.escape.checkNewEscape(dmd.dscope.Scope*,
dmd.expression.Expression, bool) (gag=false, e=0x0, sc=0x7ffffe274120) at
dmd/escape.d:592
#2  0x00000000005b8342 in ExpressionSemanticVisitor::visit(NewExp*)
(this=0x7ffffffecf08, exp=0x7fffff6b53b0) at dmd/expressionsem.d:2363
#3  0x00000000005a9ba6 in NewExp::accept(Visitor*) (this=0x7fffff6b53b0,
v=0x7ffffffecf08) at dmd/expression.d:4155
#4  0x00000000005cc5ef in expressionSemantic(Expression*, Scope*)
(e=0x7fffff6b53b0, sc=0x7ffffe274120) at dmd/expressionsem.d:9367
#5  0x000000000064f0cc in StatementSemanticVisitor::visit(ExpStatement*)
(this=0x7ffffffecfd8, s=0x7fffff6b5420) at dmd/statementsem.d:177
#6  0x0000000000631a0e in ExpStatement::accept(Visitor*) (this=0x7fffff6b5420,
v=0x7ffffffecfd8) at dmd/statement.d:715
#7  0x000000000064efa7 in statementSemantic(Statement*, Scope*)
(s=0x7fffff6b5420, sc=0x7ffffe274120) at dmd/statementsem.d:126
#8  0x000000000064f38a in StatementSemanticVisitor::visit(CompoundStatement*)
(this=0x7ffffffed2d8, cs=0x7fffff6b5440) at dmd/statementsem.d:235
#9  0x0000000000632206 in CompoundStatement::accept(Visitor*)
(this=0x7fffff6b5440, v=0x7ffffffed2d8) at dmd/statement.d:908
#10 0x000000000064efa7 in statementSemantic(Statement*, Scope*)
(s=0x7fffff6b5440, sc=0x7ffffe274120) at dmd/statementsem.d:126
#11 0x0000000000663aae in Semantic3Visitor::visit(FuncDeclaration*)
(this=0x7ffffffedb80, funcdecl=0x7fffff6b5060) at dmd/semantic3.d:581
#12 0x00000000005d35e6 in FuncDeclaration::accept(Visitor*)
(this=0x7fffff6b5060, v=0x7ffffffedb80) at dmd/func.d:2277
#13 0x00000000006623c5 in semantic3(Dsymbol*, Scope*) (dsym=0x7fffff6b5060,
sc=0x7ffffe273e30) at dmd/semantic3.d:82
#14 0x00000000006627c6 in Semantic3Visitor::visit(Module*)
(this=0x7ffffffedc30, mod=0x7fffff6b4c00) at dmd/semantic3.d:193
#15 0x000000000055838e in Module::accept(Visitor*) (this=0x7fffff6b4c00,
v=0x7ffffffedc30) at dmd/dmodule.d:1322
#16 0x00000000006623c5 in semantic3(Dsymbol*, Scope*) (dsym=0x7fffff6b4c00,
sc=0x0) at dmd/semantic3.d:82
#17 0x00000000005fd1f7 in dmd.mars.tryMain(ulong, const(char)**)
(argv=0x7ffffffee958, argc=3) at dmd/mars.d:836
#18 0x00000000005fe17b in D main () at dmd/mars.d:1098

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