diff --git a/modules/nf-lang/src/main/java/nextflow/script/control/VariableScopeVisitor.java b/modules/nf-lang/src/main/java/nextflow/script/control/VariableScopeVisitor.java
index dcb8662d40..5136b2ab25 100644
--- a/modules/nf-lang/src/main/java/nextflow/script/control/VariableScopeVisitor.java
+++ b/modules/nf-lang/src/main/java/nextflow/script/control/VariableScopeVisitor.java
@@ -306,6 +306,7 @@ private void visitTypedOutputs(Statement outputs, String typeLabel) {
             var output = es.getExpression();
             VariableExpression target;
             if( output instanceof VariableExpression ve ) {
+                visit(ve);
                 target = ve;
             }
             else if( output instanceof AssignmentExpression assign ) {
diff --git a/modules/nf-lang/src/test/groovy/nextflow/script/control/ScriptResolveTest.groovy b/modules/nf-lang/src/test/groovy/nextflow/script/control/ScriptResolveTest.groovy
index a8911f0277..3171ed978a 100644
--- a/modules/nf-lang/src/test/groovy/nextflow/script/control/ScriptResolveTest.groovy
+++ b/modules/nf-lang/src/test/groovy/nextflow/script/control/ScriptResolveTest.groovy
@@ -182,6 +182,54 @@ class ScriptResolveTest extends Specification {
         errors[0].getStartLine() == 3
         errors[0].getStartColumn() == 9
         errors[0].getOriginalMessage() == 'Variables in a closure should be declared with `def`'
+
+        when:
+        errors = check(
+            '''\
+            workflow hello {
+                emit:
+                x
+            }
+            '''
+        )
+        then:
+        errors.size() == 1
+        errors[0].getStartLine() == 3
+        errors[0].getStartColumn() == 5
+        errors[0].getOriginalMessage() == '`x` is not defined'
+
+        when:
+        errors = check(
+            '''\
+            workflow hello {
+                emit:
+                x = y
+            }
+            '''
+        )
+        then:
+        errors.size() == 1
+        errors[0].getStartLine() == 3
+        errors[0].getStartColumn() == 9
+        errors[0].getOriginalMessage() == '`y` is not defined'
+
+        when:
+        errors = check(
+            '''\
+            workflow hello {
+                emit:
+                x + y
+            }
+            '''
+        )
+        then:
+        errors.size() == 2
+        errors[0].getStartLine() == 3
+        errors[0].getStartColumn() == 5
+        errors[0].getOriginalMessage() == '`x` is not defined'
+        errors[1].getStartLine() == 3
+        errors[1].getStartColumn() == 9
+        errors[1].getOriginalMessage() == '`y` is not defined'
     }
 
     def 'should report an error for an undefined function' () {