Sol1

Author: abulgit

compiler/src/dmd/enumsem.d

@@ -236,6 +236,11 @@ void enumSemantic(Scope* sc, EnumDeclaration ed)
         if (EnumMember em = s.isEnumMember())
             em.dsymbolSemantic(em._scope);
     });
+
+    // Don't set to PASS.semanticdone here, semantic2 will complete the analysis
+    // and set it to PASS.semantic2done
+    if (!sc.inCfile)  // C enum remains incomplete until members are done
+        ed.semanticRun = PASS.semantic;
     //printf("ed.defaultval = %lld\n", ed.defaultval);
 
     //if (ed.defaultval) printf("ed.defaultval: %s %s\n", ed.defaultval.toChars(), ed.defaultval.type.toChars());
@@ -542,7 +547,7 @@ void enumMemberSemantic(Scope* sc, EnumMember em)
         emax = emax.ctfeInterpret();
 
         // check that (eprev != emax)
-        Expression e = new EqualExp(EXP.equal, em.loc, eprev, emax);
+        Expression e = new EqualExp(EXP.equal, em.ed.loc, eprev, emax);
         e = e.expressionSemantic(sc);
         e = e.ctfeInterpret();
         if (global.endGagging(errors))
@@ -553,7 +558,7 @@ void enumMemberSemantic(Scope* sc, EnumMember em)
             Expression e2 = DotIdExp.create(em.ed.loc, new TypeExp(em.ed.loc, tprev), Id.max);
             e2 = e2.expressionSemantic(sc);
             e2 = e2.ctfeInterpret();
-            e2 = new EqualExp(EXP.equal, em.loc, eprev, e2);
+            e2 = new EqualExp(EXP.equal, em.ed.loc, eprev, e2);
             e2 = e2.expressionSemantic(sc);
             e2 = e2.ctfeInterpret();
         }

compiler/src/dmd/semantic2.d

@@ -123,6 +123,28 @@ private extern(C++) final class Semantic2Visitor : Visitor
         staticAssertFail(sa, sc);
     }
 
+    override void visit(EnumDeclaration ed)
+    {
+        //printf("EnumDeclaration::semantic2(%s) %s\n", sc.stc & STCfinal ? "final" : "", ed.toChars());
+        if (ed.semanticRun >= PASS.semantic2done)
+            return;
+        ed.semanticRun = PASS.semantic2;
+
+        if (!ed.members)
+            return;
+
+        // Process all enum members to compute their values
+        for (size_t i = 0; i < ed.members.length; i++)
+        {
+            EnumMember em = (*ed.members)[i].isEnumMember();
+            if (em && em.semanticRun < PASS.semanticdone)
+                em.dsymbolSemantic(em._scope);
+        }
+
+        // Now that all member values are calculated, we can mark the enum as semantic2done
+        ed.semanticRun = PASS.semantic2done;
+    }
+
     override void visit(TemplateInstance tempinst)
     {
         if (tempinst.semanticRun >= PASS.semantic2)

compiler/src/dmd/statementsem.d

@@ -1959,6 +1959,15 @@ Statement statementSemanticVisit(Statement s, Scope* sc)
                 ed = ds.isEnumDeclaration(); // typedef'ed enum
             if (!ed && te && ((ds = te.toDsymbol(sc)) !is null))
                 ed = ds.isEnumDeclaration();
+
+            // Check if enum semantic analysis is not yet complete
+            if (ed && ed.semanticRun < PASS.semantic2done)
+            {
+                error(ss.loc, "cannot use `final switch` on enum `%s` while it is being defined", ed.toChars());
+                sc.pop();
+                return setError();
+            }
+
             if (ed && ss.cases.length < ed.members.length)
             {
                 int missingMembers = 0;

compiler/test/fail_compilation/fix20867.d

@@ -0,0 +1,20 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/fix20867.d(14): Error: cannot use `final switch` on enum `E` while it is being defined
+---
+*/
+
+// Test case from Issue #20867
+enum E
+{
+    a = 3,
+    b = () {
+        E e;
+        final switch (e)  // This should error out instead of segfaulting
+        {
+            case E.a: break;
+        }
+        return 4;
+    } ()
+}