Add a null-check in CanBeStatic

JDK 12 changes the representation of labelled breaks to use an identifier for the label (instead of just a name), and the identifier doesn't have a symbol. Fixes #1111 ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=311832221
google · May 16, 2020 · 12e2544 · 12e2544
1 parent 0202733
commit 12e2544
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Showing 2 changed files with 28 additions and 5 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/CanBeStaticAnalyzer.java b/core/src/main/java/com/google/errorprone/bugpatterns/CanBeStaticAnalyzer.java
@@ -69,23 +69,27 @@ private CanBeStaticAnalyzer(Symbol owner, VisitorState state) {
   public void visitIdent(JCTree.JCIdent tree) {
     // check for unqualified references to instance members (fields and methods) declared
     // in an enclosing scope
-    if (tree.sym.isStatic()) {
+    Symbol sym = tree.sym;
+    if (sym == null) {
+      // return;
+    }
+    if (sym.isStatic()) {
       return;
     }
-    switch (tree.sym.getKind()) {
+    switch (sym.getKind()) {
       case TYPE_PARAMETER:
         // declaring a class as non-static just to access a type parameter is silly -
         // why not just re-declare the type parameter instead of capturing it?
         // TODO(cushon): consider making the suggestion anyways, maybe with a fix?
         // fall through
       case FIELD:
-        if (!isOwnedBy(tree.sym, owner, state.getTypes())) {
+        if (!isOwnedBy(sym, owner, state.getTypes())) {
           canPossiblyBeStatic = false;
         }
         break;
       case METHOD:
-        if (!isOwnedBy(tree.sym, owner, state.getTypes())) {
-          outerReferences.add((MethodSymbol) tree.sym);
+        if (!isOwnedBy(sym, owner, state.getTypes())) {
+          outerReferences.add((MethodSymbol) sym);
         }
         break;
       case CLASS:

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/ClassCanBeStaticTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/ClassCanBeStaticTest.java
@@ -358,4 +358,23 @@ public void innerClassMethodReference() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void labelledBreak() {
+    compilationHelper
+        .addSourceLines(
+            "A.java",
+            "public class A {",
+            "  // BUG: Diagnostic contains:",
+            "  class Inner {",
+            "    void f() {",
+            "      OUTER:",
+            "      while (true) {",
+            "        break OUTER;",
+            "      }",
+            "    }",
+            "  }",
+            "}")
+        .doTest();
+  }
 }