From eb601d32427e2bdd92e03fc25f594f54f15be913 Mon Sep 17 00:00:00 2001
From: Andrii Kurdiumov <kant2002@gmail.com>
Date: Thu, 8 Feb 2024 19:15:26 +0600
Subject: [PATCH] Make sure that lowering of test expression happens in switch

---
 Cesium.CodeGen.Tests/CodeGenSwitchTests.cs    | 13 +++++++
 ...enSwitchTests.LowerExpression.verified.txt | 39 +++++++++++++++++++
 .../Ir/Lowering/BlockItemLowering.cs          |  5 ++-
 3 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 Cesium.CodeGen.Tests/verified/CodeGenSwitchTests.LowerExpression.verified.txt

diff --git a/Cesium.CodeGen.Tests/CodeGenSwitchTests.cs b/Cesium.CodeGen.Tests/CodeGenSwitchTests.cs
index 8ac6f65d..b7e36d68 100644
--- a/Cesium.CodeGen.Tests/CodeGenSwitchTests.cs
+++ b/Cesium.CodeGen.Tests/CodeGenSwitchTests.cs
@@ -102,4 +102,17 @@ public Task DeepCase() => DoTest(@"int main()
     int x = 0;
     switch(x) while (0) { default: break; }
 }");
+
+    [Fact]
+    public Task LowerExpression() => DoTest(@"
+int my_condition() { return 0; }
+int main()
+{
+    switch(my_condition()) { 
+        case 0: break;
+        case 1:
+        default: break;
+    };
+    return 1;
+}");
 }
diff --git a/Cesium.CodeGen.Tests/verified/CodeGenSwitchTests.LowerExpression.verified.txt b/Cesium.CodeGen.Tests/verified/CodeGenSwitchTests.LowerExpression.verified.txt
new file mode 100644
index 00000000..45e9b8e1
--- /dev/null
+++ b/Cesium.CodeGen.Tests/verified/CodeGenSwitchTests.LowerExpression.verified.txt
@@ -0,0 +1,39 @@
+System.Int32 <Module>::my_condition()
+  IL_0000: ldc.i4.0
+  IL_0001: ret
+
+System.Int32 <Module>::main()
+  Locals:
+    System.Int32 V_0
+  IL_0000: call System.Int32 <Module>::my_condition()
+  IL_0005: stloc.0
+  IL_0006: ldloc.0
+  IL_0007: ldc.i4.0
+  IL_0008: ceq
+  IL_000a: brfalse IL_0014
+  IL_000f: br IL_0029
+  IL_0014: nop
+  IL_0015: ldloc.0
+  IL_0016: ldc.i4.1
+  IL_0017: ceq
+  IL_0019: brfalse IL_0023
+  IL_001e: br IL_002f
+  IL_0023: nop
+  IL_0024: br IL_002f
+  IL_0029: nop
+  IL_002a: br IL_0035
+  IL_002f: nop
+  IL_0030: br IL_0035
+  IL_0035: nop
+  IL_0036: ldc.i4.1
+  IL_0037: ret
+
+System.Int32 <Module>::<SyntheticEntrypoint>()
+  Locals:
+    System.Int32 V_0
+  IL_0000: call System.Int32 <Module>::main()
+  IL_0005: stloc.s V_0
+  IL_0007: ldloc.s V_0
+  IL_0009: call System.Void Cesium.Runtime.RuntimeHelpers::Exit(System.Int32)
+  IL_000e: ldloc.s V_0
+  IL_0010: ret
diff --git a/Cesium.CodeGen/Ir/Lowering/BlockItemLowering.cs b/Cesium.CodeGen/Ir/Lowering/BlockItemLowering.cs
index 1df9eddb..5be3902f 100644
--- a/Cesium.CodeGen/Ir/Lowering/BlockItemLowering.cs
+++ b/Cesium.CodeGen/Ir/Lowering/BlockItemLowering.cs
@@ -374,13 +374,14 @@ void ProcessCaseStatement(CaseStatement caseStatement, BlockScope switchBlock, s
                         return Lower(switchScope, new ExpressionStatement(s.Expression));
                     }
 
+                    var testExpression = s.Expression.Lower(scope);
                     var dbi = new DeclarationBlockItem(
                         new ScopedIdentifierDeclaration(
                             StorageClass.Auto,
                             new List<InitializableDeclarationInfo>
                             {
-                            new(new LocalDeclarationInfo(s.Expression.GetExpressionType(scope), "$switch_tmp", null),
-                                s.Expression)
+                                new(new LocalDeclarationInfo(testExpression.GetExpressionType(scope), "$switch_tmp", null),
+                                testExpression)
                             }));
 
                     targetStmts.Add(Lower(switchScope, dbi));