Change f7819c8 to not hide behind a switch

Such bug fix is hard to hide behind a deprecation warning as it affects runtime behaviour without causing direct compilation failure, thus extra migration help is provided via -transition=safe.
dlang · Oct 8, 2016 · f55b4d9 · f55b4d9
1 parent 748549e
commit f55b4d9
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Showing 3 changed files with 42 additions and 3 deletions.
diff --git a/changelog.dd b/changelog.dd
@@ -8,12 +8,39 @@ $(BUGSTITLE Language Changes,
 )
 
 $(BUGSTITLE Compiler Changes,
+    $(LI $(RELATIVE_LINK2 iteration_closure, Assumes opApply delegate parameter escapes unless marked `scope`))
 )
 
 $(BUGSTITLE Language Changes,
 )
 
 $(BUGSTITLE Compiler Changes,
+    $(LI $(LNAME2 iteration_closure, Assumes opApply delegate parameter escapes unless marked `scope`)
+
+    $(P This breaking change was required to fix bug with `@safe` violation: $(BUGZILLA 16193).)
+
+    $(P To list all places where closure may be allocated after the change, use `-transition=safe`
+        compiler switch.)
+
+    $(P Example:)
+
+        ---
+        struct S1 {
+            int opApply(int delegate(int) dg);
+        }
+
+        struct S2 {
+            int opApply(scope int delegate(int) dg);
+        }
+
+        void foo() {
+            foreach(i; S1.init) { // will allocate closure
+            }
+            foreach(i; S2.init) { // won't allocate closure
+            }
+        }
+        ---
+    )
 )
 
 Macros:

diff --git a/src/statementsem.d b/src/statementsem.d
@@ -1448,7 +1448,16 @@ private extern (C++) final class StatementSemanticVisitor : Visitor
                 else
                 {
                     if (global.params.safe)
-                        fld.tookAddressOf = 1;  // allocate a closure unless the opApply() uses 'scope'
+                    {
+                        fprintf(
+                            global.stdmsg,
+                            "%s: To enforce @safe compiler allocates a closure unless the opApply() uses 'scope'\n",
+                            loc.toChars()
+                        );
+                        fflush(global.stdmsg);
+                    }
+                    fld.tookAddressOf = 1;
+
                     assert(tab.ty == Tstruct || tab.ty == Tclass);
                     assert(sapply);
                     /* Call:

diff --git a/test/fail_compilation/test16193.d b/test/fail_compilation/test16193.d
@@ -3,8 +3,11 @@ REQUIRED_ARGS: -transition=safe
 PERMUTE_ARGS:
 TEST_OUTPUT:
 ---
-fail_compilation/test16193.d(36): Error: function test16193.abc is @nogc yet allocates closures with the GC
-fail_compilation/test16193.d(38):        test16193.abc.__foreachbody1 closes over variable x at fail_compilation/test16193.d(37)
+fail_compilation/test16193.d(22): To enforce @safe compiler allocates a closure unless the opApply() uses 'scope'
+fail_compilation/test16193.d(34): To enforce @safe compiler allocates a closure unless the opApply() uses 'scope'
+fail_compilation/test16193.d(41): To enforce @safe compiler allocates a closure unless the opApply() uses 'scope'
+fail_compilation/test16193.d(39): Error: function test16193.abc is @nogc yet allocates closures with the GC
+fail_compilation/test16193.d(41):        test16193.abc.__foreachbody1 closes over variable x at fail_compilation/test16193.d(40)
 ---
 */