Check that verify is only used in parsers.

frontends/p4/typeChecking/typeChecker.cpp

@@ -2527,6 +2527,13 @@ const IR::Node* TypeInference::postorder(IR::MethodCallExpression* expression) {
                 ::error("%1%: tables cannot be invoked from actions", expression);
         }
 
+        // Check that verify is only invoked from parsers.
+        if (auto ef = mi->to<ExternFunction>()) {
+            if (ef->method->name == IR::ParserState::verify)
+                if (!findContext<IR::P4Parser>())
+                    ::error("%1%: may only be invoked in parsers", ef->expr);
+        }
+
         if (mi->is<ExternMethod>())
             checkCorelibMethods(mi->to<ExternMethod>());
 

testdata/p4_16_errors/control-verify.p4

@@ -0,0 +1,9 @@
+#include <core.p4>
+
+error { Oops }
+
+control C() {
+  apply {
+    verify(8w0 == 8w1, error.Oops);
+   }
+}

testdata/p4_16_errors_outputs/control-verify.p4

@@ -0,0 +1,11 @@
+error {
+    Oops
+}
+#include <core.p4>
+
+control C() {
+    apply {
+        verify(8w0 == 8w1, error.Oops);
+    }
+}
+

testdata/p4_16_errors_outputs/control-verify.p4-stderr

@@ -0,0 +1,3 @@
+../testdata/p4_16_errors/control-verify.p4(7): error: verify: may only be invoked in parsers
+    verify(8w0 == 8w1, error.Oops);
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^