Shortcut equivalence check if ctdecl is unresolved

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/codestyle/UseDiamondOperatorRule.java

@@ -133,16 +133,8 @@ public class UseDiamondOperatorRule extends AbstractJavaRulechainRule {
         MethodCallSite fakeCallSite = infer.newCallSite(mirror, targetType);
         infer.inferInvocationRecursively(fakeCallSite);
 
-        try {
-            return mirror.isEquivalentToUnderlyingAst()
-                && topmostContext.acceptsType(mirror.getInferredType());
-        } catch (IllegalStateException e) {
-            /*
-             * overload resolution may complaint it's incomplete if there are missing types.
-             * The missing type info may be relevant to the user, but this exception is not, swallow it
-             */
-            return false;
-        }
+        return mirror.isEquivalentToUnderlyingAst()
+            && topmostContext.acceptsType(mirror.getInferredType());
     }
 
 

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/types/internal/infer/ast/BaseInvocMirror.java

@@ -40,6 +40,9 @@ abstract class BaseInvocMirror<T extends InvocationNode> extends BasePolyMirror<
     public boolean isEquivalentToUnderlyingAst() {
         MethodCtDecl ctDecl = getCtDecl();
         AssertionUtil.validateState(ctDecl != null, "overload resolution is not complete");
+        if (ctDecl.isFailed()) {
+            return false; // be conservative
+        }
         if (!myNode.getMethodType().getSymbol().equals(ctDecl.getMethodType().getSymbol())) {
             return false;
         } else if (myNode instanceof ASTConstructorCall && ((ASTConstructorCall) myNode).isAnonymousClass()