fix Issue 23145 - Stack allocation of scope new variables defeats @safe (#14175)

compiler/src/dmd/clone.d

@@ -1065,7 +1065,7 @@ private DtorDeclaration buildWindowsCppDtor(AggregateDeclaration ad, DtorDeclara
 {
     auto cldec = ad.isClassDeclaration();
     if (!cldec || cldec.cppDtorVtblIndex == -1) // scalar deleting dtor not built for non-virtual dtors
-        return dtor;
+        return dtor;    // perhaps also do this if STC.scope_ is set
 
     // generate deleting C++ destructor corresponding to:
     // void* C::~C(int del)
@@ -1077,8 +1077,9 @@ private DtorDeclaration buildWindowsCppDtor(AggregateDeclaration ad, DtorDeclara
     Parameter delparam = new Parameter(STC.undefined_, Type.tuns32, Identifier.idPool("del"), new IntegerExp(dtor.loc, 0, Type.tuns32), null);
     Parameters* params = new Parameters;
     params.push(delparam);
-    auto ftype = new TypeFunction(ParameterList(params), Type.tvoidptr, LINK.cpp, dtor.storage_class);
+    const stc = dtor.storage_class & ~STC.scope_; // because we add the `return this;` later
-    auto func = new DtorDeclaration(dtor.loc, dtor.loc, dtor.storage_class, Id.cppdtor);
+    auto ftype = new TypeFunction(ParameterList(params), Type.tvoidptr, LINK.cpp, stc);
+    auto func = new DtorDeclaration(dtor.loc, dtor.loc, stc, Id.cppdtor);
     func.type = ftype;
 
     // Always generate the function with body, because it is not exported from DLLs.

compiler/src/dmd/dsymbolsem.d

@@ -1090,9 +1090,26 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
                             ex = (cast(AssignExp)ex).e2;
                         if (auto ne = ex.isNewExp())
                         {
-                            // See if initializer is a NewExp that can be allocated on the stack
+                            /* See if initializer is a NewExp that can be allocated on the stack.
+                             */
                             if (dsym.type.toBasetype().ty == Tclass)
                             {
+                                /* Unsafe to allocate on stack if constructor is not `scope` because the `this` can leak.
+                                 * https://issues.dlang.org/show_bug.cgi?id=23145
+                                 */
+                                if (ne.member && !(ne.member.storage_class & STC.scope_))
+                                {
+                                    if (sc.func.isSafe())
+                                    {
+                                        // @@@DEPRECATED_2.112@@@
+                                        deprecation(dsym.loc,
+                                            "`scope` allocation of `%s` requires that constructor be annotated with `scope`",
+                                            dsym.toChars());
+                                        deprecationSupplemental(ne.member.loc, "is the location of the constructor");
+                                     }
+                                     else
+                                         sc.func.setUnsafe();
+                                }
                                 ne.onstack = 1;
                                 dsym.onstack = true;
                             }
@@ -4199,8 +4216,8 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
 
     override void visit(DtorDeclaration dd)
     {
-        //printf("DtorDeclaration::semantic() %s\n", toChars());
+        //printf("DtorDeclaration::semantic() %s\n", dd.toChars());
-        //printf("ident: %s, %s, %p, %p\n", ident.toChars(), Id.dtor.toChars(), ident, Id.dtor);
+        //printf("ident: %s, %s, %p, %p\n", dd.ident.toChars(), Id.dtor.toChars(), dd.ident, Id.dtor);
         if (dd.semanticRun >= PASS.semanticdone)
             return;
         if (dd._scope)
@@ -5342,7 +5359,7 @@ private extern(C++) final class DsymbolSemanticVisitor : Visitor
                 // is less strict (e.g. `preview=dtorfields` might introduce a call to a less qualified dtor)
 
                 auto ctor = new CtorDeclaration(cldec.loc, Loc.initial, 0, tf);
-                ctor.storage_class |= STC.inference;
+                ctor.storage_class |= STC.inference | (fd.storage_class & STC.scope_);
                 ctor.isGenerated = true;
                 ctor.fbody = new CompoundStatement(Loc.initial, new Statements());
 

compiler/src/dmd/func.d

@@ -2320,6 +2320,7 @@ extern (C++) class FuncDeclaration : Declaration
          *    base.in();
          *    assert(false, "Logic error: " ~ thr.msg);
          *  }
+         * }
          */
 
         foreach (fdv; foverrides)
@@ -3861,7 +3862,7 @@ extern (C++) final class CtorDeclaration : FuncDeclaration
     {
         super(loc, endloc, Id.ctor, stc, type);
         this.isCpCtor = isCpCtor;
-        //printf("CtorDeclaration(loc = %s) %s\n", loc.toChars(), toChars());
+        //printf("CtorDeclaration(loc = %s) %s %p\n", loc.toChars(), toChars(), this);
     }
 
     override CtorDeclaration syntaxCopy(Dsymbol s)

compiler/src/dmd/nogc.d

@@ -13,11 +13,14 @@
 
 module dmd.nogc;
 
+import core.stdc.stdio;
+
 import dmd.aggregate;
 import dmd.apply;
 import dmd.astenums;
 import dmd.declaration;
 import dmd.dscope;
+import dmd.errors;
 import dmd.expression;
 import dmd.func;
 import dmd.globals;

compiler/test/compilable/test23145.d

@@ -0,0 +1,39 @@
+/* TEST_OUTPUT:
+---
+compilable/test23145.d(117): Deprecation: `scope` allocation of `c` requires that constructor be annotated with `scope`
+compilable/test23145.d(111):        is the location of the constructor
+compilable/test23145.d(124): Deprecation: `scope` allocation of `c` requires that constructor be annotated with `scope`
+compilable/test23145.d(111):        is the location of the constructor
+---
+*/
+
+// https://issues.dlang.org/show_bug.cgi?id=23145
+
+#line 100
+
+class D
+{
+    C c;
+}
+
+class C
+{
+    D d;
+    int x=3;
+    this(int i) scope @safe @nogc;
+    this(D d) @safe @nogc;
+}
+
+C foo(D d)@nogc @safe
+{
+    scope e = new C(1);  // ok
+    scope c = new C(d);  // deprecation
+    return c.d.c;
+}
+
+C bax(D d) @safe
+{
+    scope e = new C(1);  // ok
+    scope c = new C(d);  // deprecation
+    return c.d.c;
+}

compiler/test/runnable/auto1.d

@@ -67,13 +67,13 @@ int ax;
 
 class A2
 {
-  this()
+  this() scope
   {
     printf("A2.this()\n");
     ax += 1;
   }
 
-  ~this()
+  ~this() scope
   {
     printf("A2.~this()\n");
     ax += 1000;
@@ -102,12 +102,12 @@ class Parent3
 
 class Child3 : Parent3
 {
-        this(){
+        this() scope {
                 assert(status3==0);
                 status3=1;
         }
 
-        ~this(){
+        ~this() scope {
                 assert(status3==1);
                 status3=2;
         }

compiler/test/runnable/cppdtor.d

@@ -38,12 +38,12 @@ extern (C) int printf(scope const char*, ...);
 extern (C++) class CppA
 {
 	int num;
-	this(int num)
+	this(int num) scope
 	{
 		this.num = num;
 	}
 
-	~this()
+	~this() scope
 	{
 		printf("%d: CppA.~this\n", num);
 	}
@@ -51,12 +51,12 @@ extern (C++) class CppA
 
 extern (C++) class CppB : CppA
 {
-	this(int num)
+	this(int num) scope
 	{
 		super(num);
 	}
 
-	~this()
+	~this() scope
 	{
 		printf("%d: CppB.~this\n", num);
 	}
@@ -64,12 +64,12 @@ extern (C++) class CppB : CppA
 
 extern (C++) class CppC : CppB
 {
-	this(int num)
+	this(int num) scope
 	{
 		super(num);
 	}
 
-	~this()
+	~this() scope
 	{
 		printf("%d: CppC.~this\n", num);
 	}
@@ -78,12 +78,12 @@ extern (C++) class CppC : CppB
 extern (D) class DA
 {
 	int num;
-	this(int num)
+	this(int num) scope
 	{
 		this.num = num;
 	}
 
-	~this()
+	~this() scope
 	{
 		printf("%d: DA.~this\n", num);
 	}
@@ -91,12 +91,12 @@ extern (D) class DA
 
 extern (D) class DB : DA
 {
-	this(int num)
+	this(int num) scope
 	{
 		super(num);
 	}
 
-	~this()
+	~this() scope
 	{
 		printf("%d: DB.~this\n", num);
 	}
@@ -104,12 +104,12 @@ extern (D) class DB : DA
 
 extern (D) class DC : DB
 {
-	this(int num)
+	this(int num) scope
 	{
 		super(num);
 	}
 
-	~this()
+	~this() scope
 	{
 		printf("%d: DC.~this\n", num);
 	}
@@ -118,7 +118,7 @@ extern (D) class DC : DB
 extern (C++) class CppNoDestruct
 {
 	int num;
-	this(int num)
+	this(int num) scope
 	{
 		this.num = num;
 	}

compiler/test/runnable/mixin2.d

@@ -82,13 +82,13 @@ int x5;
 
 class Foo5
 {
-        this ()
+        this () scope
         {
                 printf ("Constructor\n");
                 assert(x5 == 0);
                 x5++;
         }
-        ~this ()
+        ~this () scope
         {
                 printf ("Destructor\n");
                 assert(x5 == 2);

compiler/test/runnable/test20855.d

@@ -4,7 +4,7 @@
 string exp()
 {
     string s = "a = b + c * d + a;";
-    foreach (i; 0 .. 9)
+    foreach (i; 0 .. 8)
 	s = s ~ s;
     return s;
 }
@@ -22,6 +22,6 @@ int main()
 {
     int a = test();
     printf("a = %d\n", a);
-    assert(test() == 7169);
+    assert(test() == 3585);
     return 0;
 }

compiler/test/runnable/test23.d

@@ -1322,22 +1322,22 @@ void test70()
 class C71
 {
     static int cnt;
-    this() { printf("C()\n"); cnt++; }
+    this() scope { printf("C()\n"); cnt++; }
-    ~this() { printf("~C()\n"); cnt--; }
+    ~this() scope { printf("~C()\n"); cnt--; }
 }
 
 class D71
 {
     static int cnt;
-    this() { printf("D()\n"); cnt++; }
+    this() scope { printf("D()\n"); cnt++; }
-    ~this() { printf("~D()\n"); cnt--; }
+    ~this() scope { printf("~D()\n"); cnt--; }
 }
 
 class E71
 {
     static int cnt;
-    this() { printf("E()\n"); cnt++; }
+    this() scope { printf("E()\n"); cnt++; }
-    ~this() { printf("~E()\n"); cnt--; }
+    ~this() scope { printf("~E()\n"); cnt--; }
 }
 
 void test71()

compiler/test/runnable/test8.d

@@ -786,8 +786,8 @@ void test42()
 int x44;
 
 class A44 {
-     this() { printf("A44 ctor\n"); x44 += 1; }
+     this() scope { printf("A44 ctor\n"); x44 += 1; }
-     ~this() { printf("A44 dtor\n"); x44 += 0x100; }
+     ~this() scope { printf("A44 dtor\n"); x44 += 0x100; }
 }
 class B44 : A44 { }
 

compiler/test/runnable/testdstress.d

@@ -494,7 +494,7 @@ void test23()
 int status24;
 
 class C24{
-        this(){
+        this() scope {
                 assert(status24==0);
                 status24+=2;
         }

compiler/test/runnable_cxx/cppa.d

@@ -1324,7 +1324,7 @@ extern(C++)
     class Cpp15589Derived : Cpp15589Base
     {
     public:
-        this();
+        this() scope;
         final ~this();
         int b;
     }
@@ -1334,7 +1334,7 @@ extern(C++)
     public:
         void beforeDtor();
 
-        this();
+        this() scope;
         ~this();
 
         void afterDtor();
@@ -1344,7 +1344,7 @@ extern(C++)
     class Cpp15589DerivedVirtual : Cpp15589BaseVirtual
     {
     public:
-        this();
+        this() scope;
         ~this();
 
         override void afterDtor();
@@ -1355,7 +1355,7 @@ extern(C++)
     class Cpp15589IntroducingVirtual : Cpp15589Base
     {
     public:
-        this();
+        this() scope;
         void beforeIntroducedVirtual();
         ~this();
         void afterIntroducedVirtual(int);