Merge pull request #10640 from WalterBright/fix20416

fix Issue 20416 - [Regression 2.073.2] compiler complains about escap…
dlang · Dec 7, 2019 · 9b0cd0d · 9b0cd0d
2 parents feef16d + a1d82c6
commit 9b0cd0d
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Showing 2 changed files with 62 additions and 2 deletions.
diff --git a/src/dmd/escape.d b/src/dmd/escape.d
@@ -1651,7 +1651,19 @@ private void escapeByValue(Expression e, EscapeByResults* er)
                         if ((stc & (STC.scope_)) && (stc & STC.return_))
                             arg.accept(this);
                         else if ((stc & (STC.ref_)) && (stc & STC.return_))
-                            escapeByRef(arg, er);
+                        {
+                            if (tf.isref)
+                            {
+                                /* Treat:
+                                 *   ref P foo(return ref P p)
+                                 * as:
+                                 *   p;
+                                 */
+                                arg.accept(this);
+                            }
+                            else
+                                escapeByRef(arg, er);
+                        }
                     }
                 }
             }
@@ -1666,7 +1678,19 @@ private void escapeByValue(Expression e, EscapeByResults* er)
                     if (ad.isClassDeclaration() || tf.isscope)       // this is 'return scope'
                         dve.e1.accept(this);
                     else if (ad.isStructDeclaration()) // this is 'return ref'
-                        escapeByRef(dve.e1, er);
+                    {
+                        if (tf.isref)
+                        {
+                            /* Treat calling:
+                             *   struct S { ref S foo() return; }
+                             * as:
+                             *   this;
+                             */
+                            dve.e1.accept(this);
+                        }
+                        else
+                            escapeByRef(dve.e1, er);
+                    }
                 }
                 else if (dve.var.storage_class & STC.return_ || tf.isreturn)
                 {

diff --git a/test/compilable/fix20416.d b/test/compilable/fix20416.d
@@ -0,0 +1,36 @@
+/* REQUIRED_ARGS: -preview=dip1000
+*/
+
+/********************************************/
+
+// https://issues.dlang.org/show_bug.cgi?id=20416
+
+alias P = int*;
+
+ref P foo(return ref P);
+
+P bar()
+{
+   P result;
+   return foo(result);
+}
+
+
+/********************************************/
+
+// https://issues.dlang.org/show_bug.cgi?id=20416
+
+
+struct S
+{
+   string x;
+   ref S foo() return;
+}
+
+
+S bar2()
+{
+   S result;
+   return result.foo();
+}
+