fix #21630: enum and alias ignored on runtime foreach loop variables

Author: tgehr

compiler/src/dmd/statementsem.d

@@ -1461,6 +1461,16 @@ Statement statementSemanticVisit(Statement s, Scope* sc)
          */
 
         //printf("ForeachRangeStatement::semantic() %p\n", fs);
+
+        if (fs.param.storageClass & STC.manifest)
+        {
+            error(fs.loc, "cannot declare `enum` loop variables for non-unrolled foreach");
+        }
+        if (fs.param.storageClass & STC.alias_)
+        {
+            error(fs.loc, "cannot declare `alias` loop variables for non-unrolled foreach");
+        }
+
         auto loc = fs.loc;
         fs.lwr = fs.lwr.expressionSemantic(sc);
         fs.lwr = resolveProperties(sc, fs.lwr);

compiler/test/fail_compilation/issue21630.d

@@ -0,0 +1,18 @@
+/+
+TEST_OUTPUT:
+---
+fail_compilation/issue21630.d(14): Error: cannot declare `enum` loop variables for non-unrolled foreach
+fail_compilation/issue21630.d(15): Error: cannot declare `alias` loop variables for non-unrolled foreach
+fail_compilation/issue21630.d(16): Error: cannot declare `enum` loop variables for non-unrolled foreach
+fail_compilation/issue21630.d(17): Error: cannot declare `alias` loop variables for non-unrolled foreach
+---
++/
+
+void main()
+{
+    enum a = [1, 2, 3];
+    foreach(enum i; a) { } // error
+    foreach(alias i; a) { } // error
+    foreach(enum i; 0 .. 3) {  } // error
+    foreach(alias i; 0 .. 3) {  } // error
+}