From 96d028ce004f5b4581997fd1d1a0ccfa87d67ea3 Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Fri, 11 Oct 2024 12:22:21 -0700
Subject: Fix a null-check bug

---
 .../src/main/java/com/seaofnodes/simple/Parser.java    |  2 +-
 .../test/java/com/seaofnodes/simple/Chapter13Test.java | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

(limited to 'chapter13')

diff --git a/chapter13/src/main/java/com/seaofnodes/simple/Parser.java b/chapter13/src/main/java/com/seaofnodes/simple/Parser.java
index 53448e4d..71bd6d02 100644
--- a/chapter13/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter13/src/main/java/com/seaofnodes/simple/Parser.java
@@ -646,7 +646,7 @@ public class Parser {
         }
 
         Type declaredType = base._fields[idx]._type;
-        return parsePostfix(new LoadNode(name, alias, declaredType, memAlias(alias), expr).peephole());
+        return parsePostfix(new LoadNode(name, alias, declaredType.glb(), memAlias(alias), expr).peephole());
     }
 
     /**
diff --git a/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java b/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java
index 3fc5502e..b425fd85 100644
--- a/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java
+++ b/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java
@@ -163,4 +163,22 @@ return new S1.s=new S2;
         StopNode stop = parser.parse().iterate(false);
         assertEquals("return new S1;", stop.toString());
     }
+
+    @Test
+    public void testcheckNull() {
+        Parser parser = new Parser(
+"""
+struct I {int i;}
+struct P {I pi;}
+P p1 = new P;
+P p2 = new P;
+p2.pi = new I;
+p2.pi.i = 2;
+if (arg) p1 = new P;
+return p1.pi.i + 1;
+""");
+        try { parser.parse(false).iterate();  fail(); }
+        catch( Exception e ) {  assertEquals("Might be null accessing 'i'",e.getMessage());  }
+    }
+
 }
-- 
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