Change switch to emit when, elsewhen, instead of when, when (#720)

Also enforce switch is conditions are mutually exclusive literals

1 files changed, 35 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/SwitchSpec.scala b/src/test/scala/chiselTests/SwitchSpec.scala
new file mode 100644
index 00000000..2cfe16d2
--- /dev/null
+++ b/src/test/scala/chiselTests/SwitchSpec.scala
@@ -0,0 +1,35 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import chisel3._
+import chisel3.util._
+import chisel3.testers.BasicTester
+
+class SwitchSpec extends ChiselFlatSpec {
+  "switch" should "require literal conditions" in {
+    a [java.lang.IllegalArgumentException] should be thrownBy {
+      elaborate(new Module {
+        val io = IO(new Bundle {})
+        val state = RegInit(0.U)
+        val wire = WireInit(0.U)
+        switch (state) {
+          is (wire) { state := 1.U }
+        }
+      })
+    }
+  }
+  it should "require mutually exclusive conditions" in {
+    a [java.lang.IllegalArgumentException] should be thrownBy {
+      elaborate(new Module {
+        val io = IO(new Bundle {})
+        val state = RegInit(0.U)
+        switch (state) {
+          is (0.U) { state := 1.U }
+          is (1.U) { state := 2.U }
+          is (0.U) { state := 3.U }
+        }
+      })
+    }
+  }
+}