From 6b848c352f0865986fc6a0ed9e09effc4f014458 Mon Sep 17 00:00:00 2001
From: k-hara <k.hara.pg@gmail.com>
Date: Wed, 30 Sep 2015 13:40:47 +0900
Subject: [PATCH] fix Issue 7979 - Alias this does not work with switch

---
 src/statement.d           | 48 ++++++++++++++++++++++++++++-----------
 test/runnable/aliasthis.d | 46 +++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 13 deletions(-)

diff --git a/src/statement.d b/src/statement.d
index 67b538a7345a..905c1d896fa3 100644
--- a/src/statement.d
+++ b/src/statement.d
@@ -11,6 +11,7 @@ module ddmd.statement;
 import core.stdc.stdarg;
 import core.stdc.stdio;
 import ddmd.aggregate;
+import ddmd.aliasthis;
 import ddmd.arrayop;
 import ddmd.arraytypes;
 import ddmd.attrib;
@@ -3614,29 +3615,50 @@ public:
         tf = sc.tf;
         if (cases)
             return this; // already run
+
         bool conditionError = false;
         condition = condition.semantic(sc);
         condition = resolveProperties(sc, condition);
+
+        Type att = null;
         TypeEnum te = null;
-        // preserve enum type for final switches
-        if (condition.type.ty == Tenum)
-            te = cast(TypeEnum)condition.type;
-        if (condition.type.isString())
+        while (condition.op != TOKerror)
         {
-            // If it's not an array, cast it to one
-            if (condition.type.ty != Tarray)
+            // preserve enum type for final switches
+            if (condition.type.ty == Tenum)
+                te = cast(TypeEnum)condition.type;
+            if (condition.type.isString())
             {
-                condition = condition.implicitCastTo(sc, condition.type.nextOf().arrayOf());
+                // If it's not an array, cast it to one
+                if (condition.type.ty != Tarray)
+                {
+                    condition = condition.implicitCastTo(sc, condition.type.nextOf().arrayOf());
+                }
+                condition.type = condition.type.constOf();
+                break;
             }
-            condition.type = condition.type.constOf();
-        }
-        else
-        {
             condition = integralPromotions(condition, sc);
-            if (condition.op != TOKerror && !condition.type.isintegral())
+            if (condition.op != TOKerror && condition.type.isintegral())
+                break;
+
+            auto ad = isAggregate(condition.type);
+            if (ad && ad.aliasthis && condition.type != att)
+            {
+                if (!att && condition.type.checkAliasThisRec())
+                    att = condition.type;
+                if (auto e = resolveAliasThis(sc, condition, true))
+                {
+                    condition = e;
+                    continue;
+                }
+            }
+
+            if (condition.op != TOKerror)
             {
-                error("'%s' must be of integral or string type, it is a %s", condition.toChars(), condition.type.toChars());
+                error("'%s' must be of integral or string type, it is a %s",
+                    condition.toChars(), condition.type.toChars());
                 conditionError = true;
+                break;
             }
         }
         condition = condition.optimize(WANTvalue);
diff --git a/test/runnable/aliasthis.d b/test/runnable/aliasthis.d
index 261c0992f4ff..47cc3f738e04 100644
--- a/test/runnable/aliasthis.d
+++ b/test/runnable/aliasthis.d
@@ -402,6 +402,11 @@ void test7()
     // Expression::checkToBoolean
     static assert(!__traits(compiles, { if (s1){} }));
     static assert(!__traits(compiles, { if (s3){} }));
+
+    // SwitchStatement::semantic
+    static assert(!__traits(compiles, { switch (c0) { default: } }));
+    static assert(!__traits(compiles, { switch (c1) { default: } }));
+    static assert(!__traits(compiles, { switch (c3) { default: } }));
 }
 
 /***************************************************/
@@ -1191,6 +1196,46 @@ void test7945()
     s.v.foo7945();      // 4.OK, ufcs
 }
 
+/***************************************************/
+// 7979
+
+void test7979()
+{
+    static struct N
+    {
+        int val;
+        alias val this;
+    }
+    N n = N(1);
+
+    switch (n)
+    {
+        case 0:
+            assert(0);
+        case 1:
+            break;
+        default:
+            assert(0);
+    }
+
+    static struct S
+    {
+        string val;
+        alias val this;
+    }
+    S s = S("b");
+
+    switch (s)
+    {
+        case "a":
+            assert(0);
+        case "b":
+            break;
+        default:
+            assert(0);
+    }
+}
+
 /***************************************************/
 // 7992
 
@@ -1902,6 +1947,7 @@ int main()
     test7731();
     test7808();
     test7945();
+    test7979();
     test7992();
     test8169();
     test8735();