fix Issue 14992 - static array local variables always require .init

Add one more special case for static array of struct initialization with zero, similar to the special case for struct initialization.

src/declaration.d

@@ -1535,24 +1535,26 @@ public:
         {
             // Provide a default initializer
             //printf("Providing default initializer for '%s'\n", toChars());
-            if (type.needsNested())
+
+            Type tv = type;
+            while (tv.ty == Tsarray)    // Don't skip Tenum
+                tv = tv.nextOf();
+            if (tv.needsNested())
             {
-                Type tv = type;
-                while (tv.toBasetype().ty == Tsarray)
-                    tv = tv.toBasetype().nextOf();
-                assert(tv.toBasetype().ty == Tstruct);
                 /* Nested struct requires valid enclosing frame pointer.
                  * In StructLiteralExp::toElem(), it's calculated.
                  */
-                checkFrameAccess(loc, sc, (cast(TypeStruct)tv.toBasetype()).sym);
+                assert(tbn.ty == Tstruct);
+                checkFrameAccess(loc, sc, (cast(TypeStruct)tbn).sym);
+
                 Expression e = tv.defaultInitLiteral(loc);
                 Expression e1 = new VarExp(loc, this);
                 e = new BlitExp(loc, e1, e);
                 e = e.semantic(sc);
                 _init = new ExpInitializer(loc, e);
                 goto Ldtor;
             }
-            else if (type.ty == Tstruct && (cast(TypeStruct)type).sym.zeroInit == 1)
+            if (tv.ty == Tstruct && (cast(TypeStruct)tv).sym.zeroInit == 1)
             {
                 /* If a struct is all zeros, as a special case
                  * set it's initializer to the integer 0.
@@ -1568,7 +1570,7 @@ public:
                 _init = new ExpInitializer(loc, e);
                 goto Ldtor;
             }
-            else if (type.baseElemOf().ty == Tvoid)
+            if (type.baseElemOf().ty == Tvoid)
             {
                 error("%s does not have a default initializer", type.toChars());
             }

src/dinterpret.d

@@ -3495,21 +3495,23 @@ public:
         Expression newval = interpret(e.e2, istate);
         if (exceptionOrCant(newval))
             return;
-        if (e.type.toBasetype().ty == Tstruct && newval.op == TOKint64)
+        if (e.op == TOKblit && newval.op == TOKint64)
         {
-            /* Look for special case of struct being initialized with 0.
-             */
-            assert(e.op == TOKconstruct || e.op == TOKblit);
-            newval = e.type.defaultInitLiteral(e.loc);
-            if (newval.op != TOKstructliteral)
+            Type tbn = e.type.baseElemOf();
+            if (tbn.ty == Tstruct)
             {
-                e.error("nested structs with constructors are not yet supported in CTFE (Bug 6419)");
-                result = CTFEExp.cantexp;
-                return;
+                /* Look for special case of struct being initialized with 0.
+                 */
+                newval = e.type.defaultInitLiteral(e.loc);
+                if (newval.op == TOKerror)
+                {
+                    result = CTFEExp.cantexp;
+                    return;
+                }
+                newval = interpret(newval, istate); // copy and set ownedByCtfe flag
+                if (exceptionOrCant(newval))
+                    return;
             }
-            newval = interpret(newval, istate); // copy and set ownedByCtfe flag
-            if (exceptionOrCant(newval))
-                return;
         }
         // ----------------------------------------------------
         //  Deal with read-modify-write assignments.

src/e2ir.c

@@ -2838,6 +2838,29 @@ elem *toElem(Expression *e, IRState *irs)
             }
             else if (t1b->ty == Tsarray)
             {
+                if (ae->op == TOKblit && ae->e2->op == TOKint64)
+                {
+                    /* Implement:
+                     *  (sarray = 0)
+                     * with:
+                     *  memset(&sarray, 0, struct.sizeof)
+                     */
+                    elem *ey = NULL;
+                    targ_size_t sz = ae->e1->type->size();
+                    StructDeclaration *sd = ((TypeStruct *)t1b->baseElemOf())->sym;
+
+                    elem *el = e1;
+                    elem *enbytes = el_long(TYsize_t, sz);
+                    elem *evalue = el_long(TYsize_t, 0);
+
+                    if (!(sd->isNested() && ae->op == TOKconstruct))
+                        el = el_una(OPaddr, TYnptr, el);
+                    e = el_param(enbytes, evalue);
+                    e = el_bin(OPmemset,TYnptr,el,e);
+                    e = el_combine(ey, e);
+                    goto Lret;
+                }
+
                 /* Implement:
                  *  (sarray = sarray)
                  */

test/runnable/imports/a14992.d

@@ -0,0 +1,5 @@
+module imports.a14992;
+
+struct S1 { }
+
+struct S2 { int v; int[] a; }

test/runnable/link14992.d

@@ -0,0 +1,22 @@
+import imports.a14992;  // do not link
+
+int test()
+{
+    S1 v1;      // OK
+    S1* p1;     // OK
+    S1[] da1;   // OK
+    S1[2] a1;   // OK <- NG
+
+    S2 v2;      // OK
+    S2* p2;     // OK
+    S2[] da2;   // OK
+    S2[2] a2;   // OK <- NG
+
+    return 1;
+}
+static assert(test());
+
+void main()
+{
+    test();
+}