Throw error when local is missing

1 files changed, 7 insertions, 1 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/llvm/LlvmCompilerContext.java b/src/main/java/org/shedlang/compiler/backends/llvm/LlvmCompilerContext.java
index d7d8c84d..60e6515b 100644
--- a/src/main/java/org/shedlang/compiler/backends/llvm/LlvmCompilerContext.java
+++ b/src/main/java/org/shedlang/compiler/backends/llvm/LlvmCompilerContext.java
@@ -78,7 +78,13 @@ public record LlvmCompilerContext(
     }
 
     public LlvmOperand local(String name) {
-        return locals.get(name);
+        var local = locals.get(name);
+        if (local == null) {
+            // TODO: better error
+            throw new RuntimeException("unrecognised local: " + name);
+        } else {
+            return local;
+        }
     }
 
     public LlvmCompilerContext addInstruction(LlvmInstruction instruction) {