fix Issue 18282 - [Scope][DIP1000]Assignment of local variable to var…

…iable not recognized by compiler

src/dmd/dcast.d

@@ -24,6 +24,7 @@ import dmd.dscope;
 import dmd.dstruct;
 import dmd.dsymbol;
 import dmd.errors;
+import dmd.escape;
 import dmd.expression;
 import dmd.expressionsem;
 import dmd.func;
@@ -2070,14 +2071,24 @@ extern (C++) Expression castTo(Expression e, Scope* sc, Type t)
             {
                 printf("ArrayLiteralExp::castTo(this=%s, type=%s, => %s)\n", e.toChars(), e.type.toChars(), t.toChars());
             }
+
+            ArrayLiteralExp ae = e;
+
+            Type tb = t.toBasetype();
+            if (tb.ty == Tarray && global.params.vsafe)
+            {
+                if (checkArrayLiteralEscape(sc, ae, false))
+                {
+                    result = new ErrorExp();
+                    return;
+                }
+            }
+
             if (e.type == t)
             {
                 result = e;
                 return;
             }
-            ArrayLiteralExp ae = e;
-
-            Type tb = t.toBasetype();
             Type typeb = e.type.toBasetype();
 
             if ((tb.ty == Tarray || tb.ty == Tsarray) &&
@@ -2166,6 +2177,7 @@ extern (C++) Expression castTo(Expression e, Scope* sc, Type t)
 
         override void visit(AssocArrayLiteralExp e)
         {
+            //printf("AssocArrayLiteralExp::castTo(this=%s, type=%s, => %s)\n", e.toChars(), e.type.toChars(), t.toChars());
             if (e.type == t)
             {
                 result = e;

src/dmd/escape.d

@@ -30,6 +30,55 @@ import dmd.tokens;
 import dmd.visitor;
 import dmd.arraytypes;
 
+/******************************************
+ * Array literal is going to be allocated on the GC heap.
+ * Check its elements to see if any would escape by going on the heap.
+ * Params:
+ *      sc = used to determine current function and module
+ *      ae = array literal expression
+ *      gag = do not print error messages
+ * Returns:
+ *      true if any elements escaped
+ */
+bool checkArrayLiteralEscape(Scope *sc, ArrayLiteralExp ae, bool gag)
+{
+    bool errors;
+    if (ae.basis)
+        errors = checkReturnEscape(sc, ae.basis, gag);
+    foreach (ex; *ae.elements)
+    {
+        if (ex)
+            errors |= checkReturnEscape(sc, ex, gag);
+    }
+    return errors;
+}
+
+/******************************************
+ * Associative array literal is going to be allocated on the GC heap.
+ * Check its elements to see if any would escape by going on the heap.
+ * Params:
+ *      sc = used to determine current function and module
+ *      ae = associative array literal expression
+ *      gag = do not print error messages
+ * Returns:
+ *      true if any elements escaped
+ */
+bool checkAssocArrayLiteralEscape(Scope *sc, AssocArrayLiteralExp ae, bool gag)
+{
+    bool errors;
+    foreach (ex; *ae.keys)
+    {
+        if (ex)
+            errors |= checkReturnEscape(sc, ex, gag);
+    }
+    foreach (ex; *ae.values)
+    {
+        if (ex)
+            errors |= checkReturnEscape(sc, ex, gag);
+    }
+    return errors;
+}
+
 /****************************************
  * Function parameter par is being initialized to arg,
  * and par may escape.
@@ -952,7 +1001,7 @@ private void escapeByValue(Expression e, EscapeByResults* er)
 
         override void visit(IndexExp e)
         {
-            if (e.type.hasPointers())
+            if (e.e1.type.toBasetype().ty == Tsarray)
             {
                 e.e1.accept(this);
             }

src/dmd/expressionsem.d

@@ -1773,6 +1773,12 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
 
         semanticTypeInfo(sc, e.type);
 
+        if (global.params.vsafe)
+        {
+            if (checkAssocArrayLiteralEscape(sc, e, false))
+                return setError();
+        }
+
         result = e;
     }
 

test/fail_compilation/retscope3.d

@@ -6,8 +6,8 @@ PERMUTE_ARGS:
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/retscope3.d(2009): Error: scope variable `arr` may not be returned
-fail_compilation/retscope3.d(2018): Error: scope variable `arr` may not be returned
+fail_compilation/retscope3.d(2008): Error: returning `& i` escapes a reference to local variable `i`
+fail_compilation/retscope3.d(2017): Error: returning `S2000(& i)` escapes a reference to local variable `i`
 ---
 */
 
@@ -21,7 +21,7 @@ int* bar1()
 {
     int i;
     int*[] arr = [ &i ];
-    return arr[0];      // Error: scope variable arr may not be returned
+    return arr[0];
 }
 
 struct S2000 { int* p; }

test/fail_compilation/test18282.d

@@ -0,0 +1,54 @@
+/* REQUIRED_ARGS: -dip1000
+   TEST_OUTPUT:
+---
+fail_compilation/test18282.d(25): Error: scope variable `aa` may not be returned
+fail_compilation/test18282.d(34): Error: returning `& i` escapes a reference to local variable `i`
+fail_compilation/test18282.d(35): Error: returning `& i` escapes a reference to local variable `i`
+fail_compilation/test18282.d(36): Error: scope variable `staa` may not be returned
+fail_compilation/test18282.d(44): Error: returning `S2000(& i)` escapes a reference to local variable `i`
+fail_compilation/test18282.d(53): Error: returning `& i` escapes a reference to local variable `i`
+fail_compilation/test18282.d(53): Error: returning `& c` escapes a reference to local variable `c`
+---
+ */
+
+// https://issues.dlang.org/show_bug.cgi?id=18282
+
+string* f() @safe
+{
+    scope string*[] ls;
+    return ls[0];
+}
+
+int* g() @safe
+{
+    scope int*[3] aa;
+    return aa[0];
+}
+
+@safe:
+
+auto bar1()
+{
+    int i = void;
+    int*[1] staa = [ &i ];
+    auto    dyna = [ &i ];
+    int*[ ] dynb = [ &i ];
+    return staa[0];
+}
+
+struct S2000 { int* p; }
+
+S2000 bar2()
+{
+    int i;
+    S2000[] arr = [ S2000(&i) ];
+    return arr[0];
+}
+
+
+void bar2()
+{
+    int i;
+    char c;
+    char*[int*] aa = [ &i : &c ];
+}