Merge pull request #7120 from tgehr/fix17807

fix Issue 17807 - Spurious dead code warnings on enum and static variables.

src/ddmd/expression.d

@@ -3594,6 +3594,11 @@ extern (C++) abstract class Expression : RootObject
         return .op_overload(this, sc);
     }
 
+    bool hasCode()
+    {
+        return true;
+    }
+
     void accept(Visitor v)
     {
         v.visit(this);
@@ -5713,6 +5718,15 @@ extern (C++) final class DeclarationExp : Expression
         return new DeclarationExp(loc, declaration.syntaxCopy(null));
     }
 
+    override bool hasCode()
+    {
+        if (auto vd = declaration.isVarDeclaration())
+        {
+            return !(vd.storage_class & (STCmanifest | STCstatic));
+        }
+        return false;
+    }
+
     override void accept(Visitor v)
     {
         v.visit(this);

src/ddmd/expression.h

@@ -214,6 +214,11 @@ class Expression : public RootObject
         return ::op_overload(this, sc);
     }
 
+    virtual bool hasCode()
+    {
+        return true;
+    }
+
     virtual void accept(Visitor *v) { v->visit(this); }
 };
 
@@ -612,6 +617,8 @@ class DeclarationExp : public Expression
 
     Expression *syntaxCopy();
 
+    bool hasCode();
+
     void accept(Visitor *v) { v->visit(this); }
 };
 

src/ddmd/statement.d

@@ -272,7 +272,10 @@ extern (C++) abstract class Statement : RootObject
 
             override void visit(ExpStatement s)
             {
-                stop = s.exp !is null;
+                if (s.exp !is null)
+                {
+                    stop = s.exp.hasCode();
+                }
             }
 
             override void visit(CompoundStatement s)

test/compilable/test17807.d

@@ -0,0 +1,17 @@
+// REQUIRED_ARGS: -o- -w
+
+int bug17807(){
+    int y=0;
+    Lswitch: switch(2){
+        { case 0: break; }
+        enum x=0;
+        struct S{ enum x=0; }
+        int foo(){
+            return 0;
+        }
+        default: y=x+S.x+foo();
+        static foreach(i;1..5)
+            case i: break Lswitch;
+    }
+    return y;
+}