Make RefactorSwitch an error

The switch statements in DimensionHelpers.extractDims,
CommandLineOptionsParser's two range parsers and SnippetFormatter's
snippetWrapper returned from every case. Each is now the switch
expression it returns, with yield where a case has statements before
its value.

Author: abashev

buildSrc/src/main/groovy/open-java-format.error-prone-conventions.gradle

@@ -55,6 +55,7 @@ tasks.withType(JavaCompile).configureEach {
 // Checks whose findings have been fixed, build-breaking so that new ones are fixed too rather than read past.
 tasks.withType(JavaCompile).configureEach {
     options.errorprone {
+        error('RefactorSwitch')
         error('SameNameButDifferent')
         error('UnusedVariable')
     }

open-java-format-eclipse-plugin/src/main/java/com/palantir/javaformat/java/SnippetFormatter.java

@@ -159,15 +159,15 @@ private SnippetWrapper snippetWrapper(SnippetKind kind, String source, int initi
          * dummy class is correctly formatted -- the blocks use correct indentation,
          * etc.
          */
-        switch (kind) {
+        return switch (kind) {
             case COMPILATION_UNIT -> {
                 SnippetWrapper wrapper = new SnippetWrapper();
                 for (int i = 1; i <= initialIndent; i++) {
                     wrapper.append("class Dummy {\n").append(createIndentationString(i));
                 }
                 wrapper.appendSource(source);
                 wrapper.closeBraces(initialIndent);
-                return wrapper;
+                yield wrapper;
             }
             case CLASS_BODY_DECLARATIONS -> {
                 SnippetWrapper wrapper = new SnippetWrapper();
@@ -176,7 +176,7 @@ private SnippetWrapper snippetWrapper(SnippetKind kind, String source, int initi
                 }
                 wrapper.appendSource(source);
                 wrapper.closeBraces(initialIndent);
-                return wrapper;
+                yield wrapper;
             }
             case STATEMENTS -> {
                 SnippetWrapper wrapper = new SnippetWrapper();
@@ -186,7 +186,7 @@ private SnippetWrapper snippetWrapper(SnippetKind kind, String source, int initi
                 }
                 wrapper.appendSource(source);
                 wrapper.closeBraces(initialIndent);
-                return wrapper;
+                yield wrapper;
             }
             case EXPRESSION -> {
                 SnippetWrapper wrapper = new SnippetWrapper();
@@ -198,9 +198,9 @@ private SnippetWrapper snippetWrapper(SnippetKind kind, String source, int initi
                 wrapper.appendSource(source);
                 wrapper.append(";");
                 wrapper.closeBraces(initialIndent);
-                return wrapper;
+                yield wrapper;
             }
             default -> throw new IllegalArgumentException("Unknown snippet kind: " + kind);
-        }
+        };
     }
 }

open-java-format/src/main/java/com/palantir/javaformat/java/CommandLineOptionsParser.java

@@ -141,18 +141,18 @@ private static void parseCharacterRanges(ImmutableRangeSet.Builder<Integer> resu
      */
     private static Range<Integer> parseCharacterRange(String range) {
         List<String> args = COLON_SPLITTER.splitToList(range);
-        switch (args.size()) {
+        return switch (args.size()) {
             case 1 -> {
                 int lowerUpperRange = Integer.parseInt(args.get(0));
-                return Range.closed(lowerUpperRange, lowerUpperRange);
+                yield Range.closed(lowerUpperRange, lowerUpperRange);
             }
             case 2 -> {
                 int lower = Integer.parseInt(args.get(0));
                 int higher = Integer.parseInt(args.get(1));
-                return Range.closed(lower, higher);
+                yield Range.closed(lower, higher);
             }
             default -> throw new IllegalArgumentException(range);
-        }
+        };
     }
 
     /**
@@ -172,18 +172,18 @@ private static void parseRangeSet(RangeSet<Integer> result, String ranges) {
      */
     private static Range<Integer> parseRange(String arg) {
         List<String> args = COLON_SPLITTER.splitToList(arg);
-        switch (args.size()) {
+        return switch (args.size()) {
             case 1 -> {
                 int line = Integer.parseInt(args.get(0)) - 1;
-                return Range.closedOpen(line, line + 1);
+                yield Range.closedOpen(line, line + 1);
             }
             case 2 -> {
                 int line0 = Integer.parseInt(args.get(0)) - 1;
                 int line1 = Integer.parseInt(args.get(1)) - 1;
-                return Range.closedOpen(line0, line1 + 1);
+                yield Range.closedOpen(line0, line1 + 1);
             }
             default -> throw new IllegalArgumentException(arg);
-        }
+        };
     }
 
     /**

open-java-format/src/main/java/com/palantir/javaformat/java/DimensionHelpers.java

@@ -102,22 +102,18 @@ private static Iterable<List<AnnotationTree>> reorderBySourcePosition(Deque<List
      * <p>Given {@code int @A @B [][] @C []}, adds {@code [[@A, @B], [@C]]} to dims and returns {@code int}.
      */
     private static Tree extractDims(Deque<List<AnnotationTree>> dims, Tree node) {
-        switch (node.getKind()) {
-            case ARRAY_TYPE -> {
-                return extractDims(dims, ((ArrayTypeTree) node).getType());
-            }
+        return switch (node.getKind()) {
+            case ARRAY_TYPE -> extractDims(dims, ((ArrayTypeTree) node).getType());
             case ANNOTATED_TYPE -> {
                 AnnotatedTypeTree annotatedTypeTree = (AnnotatedTypeTree) node;
                 if (!(annotatedTypeTree.getUnderlyingType() instanceof ArrayTypeTree)) {
-                    return node;
+                    yield node;
                 }
                 node = extractDims(dims, annotatedTypeTree.getUnderlyingType());
                 dims.addFirst(ImmutableList.copyOf(annotatedTypeTree.getAnnotations()));
-                return node;
-            }
-            default -> {
-                return node;
+                yield node;
             }
-        }
+            default -> node;
+        };
     }
 }