Test case for issue #3281

checker/tests/regex/Issue3281.java

@@ -0,0 +1,66 @@
+// Test case for Issue 3281:
+// https://github.com/typetools/checker-framework/issues/3281
+
+// @skip-test until the bug is fixed
+
+import org.checkerframework.checker.regex.RegexUtil;
+import org.checkerframework.checker.regex.qual.Regex;
+
+public class Issue3281 {
+
+    @Regex String f = null;
+
+    public boolean b = false;
+
+    void m1(String s) {
+        if (true) {
+            // :: error: (argument.type.incompatible)
+            Pattern.compile(s);
+        }
+    }
+
+    void m2(String s) {
+        RegexUtil.isRegex(s);
+        if (true) {
+            // :: error: (argument.type.incompatible)
+            Pattern.compile(s);
+        }
+    }
+
+    void m2f(String s) {
+        RegexUtil.isRegex(s);
+        if (true) {
+            // :: error: (assignment.type.incompatible)
+            f = s;
+        }
+    }
+
+    void m3(String s) {
+        if (RegexUtil.isRegex(s)) {
+            Pattern.compile(s);
+        }
+    }
+
+    void m4(String s, String s2) {
+        RegexUtil.isRegex(s);
+        if (RegexUtil.isRegex(s2)) {
+            Pattern.compile(s);
+        }
+    }
+
+    void m4f(String s, String s2) {
+        RegexUtil.isRegex(s);
+        if (RegexUtil.isRegex(s2)) {
+            // :: error: (assignment.type.incompatible)
+            f = s;
+        }
+    }
+
+    void m5f(String s, String s2) {
+        RegexUtil.isRegex(s);
+        if (b) {
+            // :: error: (assignment.type.incompatible)
+            f = s;
+        }
+    }
+}

dataflow/src/main/java/org/checkerframework/dataflow/cfg/CFGBuilder.java

@@ -2718,9 +2718,6 @@ public MethodInvocationNode visitMethodInvocation(MethodInvocationTree tree, Voi
                 return null;
             }
 
-            // TODO? Variable wasn't used.
-            // boolean isBooleanMethod = TypesUtils.isBooleanType(method.getReturnType());
-
             ExpressionTree methodSelect = tree.getMethodSelect();
             assert TreeUtils.isMethodAccess(methodSelect)
                     : "Expected a method access, but got: " + methodSelect;