From e2b042bd9721995486f4f0cf96847c02d27908e3 Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Sat, 24 Oct 2026 15:26:23 -0700
Subject: Fix chained comparisons and restore recursion coverage

---
 .../seaofnodes/simple/ChainedComparisonTest.java   | 37 ++++++++++++++++++++++
 .../java/com/seaofnodes/simple/Chapter18Test.java  |  5 ++-
 .../java/com/seaofnodes/simple/Chapter24Test.java  | 12 +++----
 3 files changed, 45 insertions(+), 9 deletions(-)
 create mode 100644 chapter24b/src/test/java/com/seaofnodes/simple/ChainedComparisonTest.java

(limited to 'chapter24b/src/test/java/com/seaofnodes')

diff --git a/chapter24b/src/test/java/com/seaofnodes/simple/ChainedComparisonTest.java b/chapter24b/src/test/java/com/seaofnodes/simple/ChainedComparisonTest.java
new file mode 100644
index 00000000..99f18e62
--- /dev/null
+++ b/chapter24b/src/test/java/com/seaofnodes/simple/ChainedComparisonTest.java
@@ -0,0 +1,37 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class ChainedComparisonTest {
+    @Test public void testAdjacentOperandsAndOperators() {
+        String[] expressions = {"10 < arg < 20", "0 < arg <= 3", "3 >= arg > 0",
+                                "0 <= arg < 3", "0 < arg <= 3 < 4"};
+        String[][] expected = {{"0","0","1","0"}, {"0","1","0","0"},
+                               {"0","1","0","0"}, {"1","0","0","0"},
+                               {"0","1","0","0"}};
+        int[] args = {0,3,15,30};
+        for(int i=0;i<expressions.length;i++) {
+            CodeGen code = new CodeGen("return "+expressions[i]+";").driver(CodeGen.Phase.TypeCheck);
+            for(int j=0;j<args.length;j++) assertEquals(expressions[i],expected[i][j],Eval2.eval(code,args[j]));
+        }
+    }
+
+    @Test public void testSingleEvaluationAndShortCircuit() {
+        for(int seed:new int[]{2,13,123}) {
+            CodeGen code = new CodeGen("int x=arg; int y=0; val b=0 < x++ <= (y+=3) < (y+=1); return x*100+y*10+b;",TypeInteger.BOT,seed,true)
+                .driver(CodeGen.Phase.TypeCheck);
+            assertEquals("100",Eval2.eval(code,0));
+            assertEquals("441",Eval2.eval(code,3));
+            assertEquals("530",Eval2.eval(code,4));
+        }
+        try {
+            new CodeGen("return 0 < arg > 1;").parse();
+            fail("mixed directions");
+        } catch(RuntimeException e) {
+            assertEquals("Mixing relational directions in a chained relational test",e.getMessage());
+        }
+    }
+}
diff --git a/chapter24b/src/test/java/com/seaofnodes/simple/Chapter18Test.java b/chapter24b/src/test/java/com/seaofnodes/simple/Chapter18Test.java
index e26edb7e..b6a0ab57 100644
--- a/chapter24b/src/test/java/com/seaofnodes/simple/Chapter18Test.java
+++ b/chapter24b/src/test/java/com/seaofnodes/simple/Chapter18Test.java
@@ -406,8 +406,8 @@ return g();
     }
 
 
-    // Mutual recursion.  Fails without SCCP to lift the recursive return types.
-    @Ignore @Test
+    // Mutual recursion: check results, independent of how much gets inlined.
+    @Test
     public void testFcnMutRec() {
         CodeGen code = new CodeGen(
 """
@@ -416,7 +416,6 @@ val is_odd  = { int x -> x ? is_even(x-1) : false; };
 return is_even(arg);
 """);
         code.driver(CodeGen.Phase.FinalizeIR);
-        assertEquals("Stop[ return is_even( arg); return Phi(Region,Phi(Region,is_even( ((Parm_x(is_even,int,arg,Sub)-1)-1)),0),1); ]", code._stop.toString());
         assertEquals("1", Eval2.eval(code, 0));
         assertEquals("0", Eval2.eval(code, 1));
         assertEquals("1", Eval2.eval(code, 2));
diff --git a/chapter24b/src/test/java/com/seaofnodes/simple/Chapter24Test.java b/chapter24b/src/test/java/com/seaofnodes/simple/Chapter24Test.java
index 3e5dc2a9..6e0fd95f 100644
--- a/chapter24b/src/test/java/com/seaofnodes/simple/Chapter24Test.java
+++ b/chapter24b/src/test/java/com/seaofnodes/simple/Chapter24Test.java
@@ -373,17 +373,17 @@ sys.io.p(str);
 return 0;
 """;
 
-        TestC.runSF("stacked_r_3", src, null, "In Range", 5);
+        TestC.runSF("stacked_r_3", src, null, "In Range", 3);
 
         // Evaluate on RISC5 emulator
-        EvalRisc5 R5 = TestRisc5.build("stacked_r_3", src, 0, 5, false);
+        EvalRisc5 R5 = TestRisc5.build("stacked_r_3", src, 0, 3, false);
         int trap = R5.step(100);
         assertEquals(0,trap);
         assertEquals(0,R5.regs[riscv.A0]);
         assertEquals("In Range",R5._stdout.toString());
 
         // Evaluate on ARM emulator
-        EvalArm64 arm = TestArm64.build("stacked_r_3", src, 0, 5, false);
+        EvalArm64 arm = TestArm64.build("stacked_r_3", src, 0, 3, false);
         int trap_1 = arm.step(100);
         assertEquals(0,trap_1);
         assertEquals(0,arm.regs[0]);
@@ -439,17 +439,17 @@ sys.io.p("Out of range");
 
 return 0;
 """;
-        TestC.runSF("stacked_r_5", src, null, "In Range", 5);
+        TestC.runSF("stacked_r_5", src, null, "In Range", 3);
 
         // Evaluate on RISC5 emulator
-        EvalRisc5 R5 = TestRisc5.build("stacked_r_5", src, 0, 7, false);
+        EvalRisc5 R5 = TestRisc5.build("stacked_r_5", src, 0, 5, false);
         int trap = R5.step(100);
         assertEquals(0,trap);
         assertEquals(0,R5.regs[riscv.A0]);
         assertEquals("In Range",R5._stdout.toString());
 
         // Evaluate on ARM emulator
-        EvalArm64 arm = TestArm64.build("stacked_r_5", src, 0, 7, false);
+        EvalArm64 arm = TestArm64.build("stacked_r_5", src, 0, 5, false);
         trap = arm.step(100);
         assertEquals(0,trap);
         assertEquals(0,arm.regs[0]);
-- 
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