Introduce NewStringFromCharArray{,SubSequence} Refaster rules (#1012)

Resolves #1001.

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StringRules.java

@@ -162,6 +162,39 @@ final class StringRules {
     }
   }
 
+  /**
+   * Prefer direct invocation of {@link String#String(char[], int, int)} over the indirection
+   * introduced by alternatives.
+   */
+  static final class NewStringFromCharArraySubSequence {
+    @BeforeTemplate
+    String before(char[] data, int offset, int count) {
+      return Refaster.anyOf(
+          String.valueOf(data, offset, count), String.copyValueOf(data, offset, count));
+    }
+
+    @AfterTemplate
+    String after(char[] data, int offset, int count) {
+      return new String(data, offset, count);
+    }
+  }
+
+  /**
+   * Prefer direct invocation of {@link String#String(char[])} over the indirection introduced by
+   * alternatives.
+   */
+  static final class NewStringFromCharArray {
+    @BeforeTemplate
+    String before(char[] data) {
+      return Refaster.anyOf(String.valueOf(data), new String(data, 0, data.length));
+    }
+
+    @AfterTemplate
+    String after(char[] data) {
+      return new String(data);
+    }
+  }
+
   /**
    * Prefer direct delegation to {@link String#valueOf(Object)} over the indirection introduced by
    * {@link Objects#toString(Object)}.

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StringRulesTestInput.java

@@ -73,6 +73,18 @@ final class StringRulesTest implements RefasterRuleCollectionTestCase {
     return Objects.toString("foo");
   }
 
+  ImmutableSet<String> testNewStringFromCharArraySubSequence() {
+    return ImmutableSet.of(
+        String.valueOf(new char[] {'f', 'o', 'o'}, 0, 1),
+        String.copyValueOf(new char[] {'b', 'a', 'r'}, 2, 3));
+  }
+
+  ImmutableSet<String> testNewStringFromCharArray() {
+    return ImmutableSet.of(
+        String.valueOf(new char[] {'f', 'o', 'o'}),
+        new String(new char[] {'b', 'a', 'r'}, 0, new char[] {'b', 'a', 'r'}.length));
+  }
+
   Function<Object, String> testStringValueOfMethodReference() {
     return Objects::toString;
   }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StringRulesTestOutput.java

@@ -75,6 +75,16 @@ final class StringRulesTest implements RefasterRuleCollectionTestCase {
     return String.valueOf("foo");
   }
 
+  ImmutableSet<String> testNewStringFromCharArraySubSequence() {
+    return ImmutableSet.of(
+        new String(new char[] {'f', 'o', 'o'}, 0, 1), new String(new char[] {'b', 'a', 'r'}, 2, 3));
+  }
+
+  ImmutableSet<String> testNewStringFromCharArray() {
+    return ImmutableSet.of(
+        new String(new char[] {'f', 'o', 'o'}), new String(new char[] {'b', 'a', 'r'}));
+  }
+
   Function<Object, String> testStringValueOfMethodReference() {
     return String::valueOf;
   }