Ignore primitive casts in ClassCastLambdaUsage check (#1385)

PicnicSupermarket · Oct 30, 2024 · ce6931c · ce6931c
1 parent 9940576
commit ce6931c
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Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/...-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ClassCastLambdaUsage.java b/...-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ClassCastLambdaUsage.java
@@ -48,7 +48,14 @@ public Description matchLambdaExpression(LambdaExpressionTree tree, VisitorState
     }
 
     Type type = ASTHelpers.getType(typeCast);
-    if (type == null || type.isParameterized()) {
+    if (type == null || type.isParameterized() || type.isPrimitive()) {
+      /*
+       * The method reference syntax does not support casting to parameterized types. Additionally,
+       * `Class#cast` does not support the same range of type conversions between (boxed) primitive
+       * types as the cast operator.
+       */
+      // XXX: Depending on the declared type of the value being cast, in some cases we _can_ rewrite
+      // primitive casts. Add support for this.
       return Description.NO_MATCH;
     }
 

diff --git a/...ne-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/ClassCastLambdaUsageTest.java b/...ne-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/ClassCastLambdaUsageTest.java
@@ -12,6 +12,7 @@ void identification() {
         .addSourceLines(
             "A.java",
             "import com.google.common.collect.ImmutableSet;",
+            "import java.util.stream.IntStream;",
             "import java.util.stream.Stream;",
             "",
             "class A {",
@@ -31,9 +32,10 @@ void identification() {
             "            i -> {",
             "              return (Integer) i;",
             "            });",
-            "    Stream.<ImmutableSet>of(ImmutableSet.of(5)).map(l -> (ImmutableSet<Number>) l);",
-            "    Stream.of(ImmutableSet.of(6)).map(l -> (ImmutableSet<?>) l);",
+            "    Stream.<ImmutableSet>of(ImmutableSet.of(5)).map(s -> (ImmutableSet<Number>) s);",
+            "    Stream.of(ImmutableSet.of(6)).map(s -> (ImmutableSet<?>) s);",
             "    Stream.of(7).reduce((a, b) -> (Integer) a);",
+            "    IntStream.of(8).mapToObj(i -> (char) i);",
             "",
             "    // BUG: Diagnostic contains:",
             "    Stream.of(8).map(i -> (Integer) i);",