Improve NullArgumentForNonNullParameter to include parameter and method names in the diagnostic message.

core/src/main/java/com/google/errorprone/bugpatterns/nullness/NullArgumentForNonNullParameter.java

@@ -51,6 +51,7 @@
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.TryTree;
 import com.sun.tools.javac.code.Symbol;
+import com.sun.tools.javac.code.Symbol.ClassSymbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.code.Symbol.VarSymbol;
 import com.sun.tools.javac.code.Type;
@@ -145,7 +146,23 @@ private Description match(
             return;
           }
 
-          state.reportMatch(describeMatch(argTree));
+          String ownerName = methodSymbol.owner.getSimpleName().toString();
+          if (ownerName.isEmpty() && methodSymbol.owner instanceof ClassSymbol) {
+            /*
+             * TODO(cpovirk): Add a test for this once we fix the
+             * hasExtraParameterForEnclosingInstance case.
+             */
+            ownerName =
+                ((ClassSymbol) methodSymbol.owner).getSuperclass().tsym.getSimpleName().toString();
+          }
+
+          String message =
+              String.format(
+                  "Null is not permitted for parameter '%s' of %s '%s'.",
+                  paramSymbol.getSimpleName(),
+                  methodSymbol.isConstructor() ? "constructor" : "method",
+                  methodSymbol.isConstructor() ? ownerName : methodSymbol.getSimpleName());
+          state.reportMatch(buildDescription(argTree).setMessage(message).build());
         });
 
     return NO_MATCH; // Any matches were reported through state.reportMatch.

core/src/test/java/com/google/errorprone/bugpatterns/nullness/NullArgumentForNonNullParameterTest.java

@@ -30,6 +30,27 @@ public class NullArgumentForNonNullParameterTest {
       CompilationTestHelper.newInstance(NullArgumentForNonNullParameter.class, getClass())
           .setArgs("-XepOpt:Nullness:Conservative=false");
 
+  @Test
+  public void positiveConstructor() {
+    aggressiveHelper
+        .addSourceLines(
+            "Foo.java",
+            """
+            import org.jspecify.annotations.NullMarked;
+
+            @NullMarked
+            class Foo {
+              Foo(String s) {}
+
+              void foo() {
+                // BUG: Diagnostic contains: parameter 's' of constructor 'Foo'
+                new Foo(null);
+              }
+            }
+            """)
+        .doTest();
+  }
+
   @Test
   public void positivePrimitive() {
     conservativeHelper
@@ -42,7 +63,7 @@ class Foo {
               void consume(int i) {}
 
               void foo(Optional<Integer> o) {
-                // BUG: Diagnostic contains:
+                // BUG: Diagnostic contains: parameter 'i' of method 'consume'
                 consume(o.orElse(null));
               }
             }
@@ -99,7 +120,7 @@ public void positiveJavaOptionalOf() {
 
             class Foo {
               void foo() {
-                // BUG: Diagnostic contains:
+                // BUG: Diagnostic contains: parameter 'value' of method 'of'
                 Optional.of(null);
               }
             }