Closes #73: Fix bug where we detect unreachable case pattern when usi…

…ng 'if' in pattern
jaccomoc · Dec 12, 2024 · 3f140ab · 3f140ab
1 parent 5ecf45a
commit 3f140ab
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Showing 2 changed files with 10 additions and 5 deletions.
diff --git a/src/main/java/io/jactl/resolver/SwitchResolver.java b/src/main/java/io/jactl/resolver/SwitchResolver.java
@@ -47,12 +47,14 @@ public static JactlType visitSwitch(Resolver resolver, Expr.Switch expr) {
 
     // Check that if there is a pattern covering all cases that there are no subsequent patterns and no default
     Set<JactlType> coveredTypes = new HashSet<>();
-    expr.cases.forEach(c -> c.patterns.stream().map(pair -> pair.first).forEach(p -> {
-      JactlType type = coveringType(p);
-      if (coveredTypes.stream().anyMatch(ct -> ct.is(ANY) || ct.is(subjectType) || ct.isAssignableFrom(p.type) || (type != null && ct.isAssignableFrom(type)))) {
-        resolver.error("Unreachable switch case (covered by a previous case)", p.location);
+    expr.cases.forEach(c -> c.patterns.stream().forEach(pair -> {
+      Expr pattern = pair.first;
+      Expr ifCond  = pair.second;
+      JactlType type = coveringType(pattern);
+      if (coveredTypes.stream().anyMatch(ct -> ct.is(ANY) || ct.is(subjectType) || ct.isAssignableFrom(pattern.type) || (type != null && ct.isAssignableFrom(type)))) {
+        resolver.error("Unreachable switch case (covered by a previous case)", pattern.location);
       }
-      if (type != null) {
+      if (type != null && ifCond == null) {
         coveredTypes.add(type);
       }
     }));

diff --git a/src/test/java/io/jactl/SwitchTests.java b/src/test/java/io/jactl/SwitchTests.java
@@ -590,6 +590,9 @@ public class SwitchTests extends BaseTest {
     test("def x = [[[3,7]],[[4,9]]]; switch (x) { [[_],[[3,7]]] -> 3; [[[3,7]],_] -> 4; _ -> null }", 4);
     test("def x = [[[3,7]],[[4,9]]]; switch (x) { [[_],[[3,7]]] -> 3; [_,[a]] -> a; _ -> null } == [4,9]", true);
     test("def x = [[[3,7]],[[4,9]]]; switch (x) { [[_],[[3,7]]] -> 3; [_,[List a]] -> a; _ -> null } == [4,9]", true);
+    test("switch (3) {\n  int if it == 3 -> '3'\n  int -> 'something else'\n}", "3");
+    test("def x = [1,2,3]; switch (x) { _ if it.size() == 2 -> 2; _ if it.size() == 3 -> 3 }", 3);
+    testError("def x = [1,2,3]; switch (x) { _ -> 2; _ if it.size() == 3 -> 3 }", "unreachable switch case");
   }
 
   @Test public void switchArrays() {