Strengthened tests and preview gating for NR1

Author: biboudis

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java

@@ -102,6 +102,7 @@ public class Types {
 
     public final Warner noWarnings;
     public final boolean dumpStacktraceOnError;
+    private final Preview preview;
     private final boolean allowEnhancedVariableDecls;
 
     // <editor-fold defaultstate="collapsed" desc="Instantiating">
@@ -118,7 +119,7 @@ protected Types(Context context) {
         syms = Symtab.instance(context);
         names = Names.instance(context);
         Source source = Source.instance(context);
-        Preview preview = Preview.instance(context);
+        preview = Preview.instance(context);
         chk = Check.instance(context);
         enter = Enter.instance(context);
         capturedName = names.fromString("<captured wildcard>");
@@ -2411,11 +2412,16 @@ public boolean isAssignable(Type t, Type s, Warner warn) {
                 break;
             }
         }
-        if (allowEnhancedVariableDecls && isNR1S(t, s)) {
+
+        if (isConvertible(t, s, warn)) {
             return true;
-        }
-        else {
-            return isConvertible(t, s, warn);
+        } else if (allowEnhancedVariableDecls && isNR1S(t, s)){
+            if (warn.pos() != null) {
+                preview.warnPreview(warn.pos(), Feature.ENHANCED_VARIABLE_DECLS);
+            }
+            return true;
+        } else {
+            return false;
         }
     }
     // where

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java

@@ -1322,10 +1322,6 @@ public void visitVarDef(JCVariableDecl tree) {
                 if (tree.isImplicitlyTyped()) {
                     setupImplicitlyTypedVariable(tree, v.type);
                 }
-
-                if (types.isNR1S(tree.init.type, v.type)) {
-                    preview.checkSourceLevel(tree.init.pos(), Feature.ENHANCED_VARIABLE_DECLS);
-                }
             }
             result = tree.type = v.type;
             if (env.enclClass.sym.isRecord() && tree.sym.owner.kind == TYP && !v.isStatic()) {

test/langtools/tools/javac/patterns/AssignmentNR1S.java

@@ -2,7 +2,7 @@
  * @test /nodynamiccopyright/
  * @summary
  * @compile/fail/ref=AssignmentNR1SNoPreview.out -XDrawDiagnostics AssignmentNR1S.java
- * @compile --enable-preview --source ${jdk.version} AssignmentNR1S.java
+ * @compile/ref=AssignmentNR1S.preview.out -XDrawDiagnostics -Xlint:preview --enable-preview --source ${jdk.version} AssignmentNR1S.java
  * @run main/othervm --enable-preview AssignmentNR1S
  */
 import java.util.Objects;

test/langtools/tools/javac/patterns/AssignmentNR1S.preview.out

@@ -0,0 +1,9 @@
+AssignmentNR1S.java:27:18: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:32:17: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:36:16: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:43:21: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:50:17: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:58:14: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:64:27: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+AssignmentNR1S.java:71:16: compiler.warn.preview.feature.use.plural: (compiler.misc.feature.enhanced.variable.decls)
+8 warnings