Add mono tests for opaque pattern with as

crates/compiler/test_mono/generated/opaque_as_pattern_in_closure_arg.txt

@@ -0,0 +1,18 @@
+procedure Num.21 (#Attr.2, #Attr.3):
+    let Num.281 : U64 = lowlevel NumMul #Attr.2 #Attr.3;
+    ret Num.281;
+
+procedure Test.2 (Test.8):
+    let Test.14 : U64 = 2i64;
+    let Test.13 : U64 = CallByName Num.21 Test.8 Test.14;
+    ret Test.13;
+
+procedure Test.3 (Test.7):
+    let Test.12 : U64 = CallByName Test.2 Test.7;
+    let Test.11 : {U64, U64} = Struct {Test.7, Test.12};
+    ret Test.11;
+
+procedure Test.0 ():
+    let Test.10 : U64 = 42i64;
+    let Test.9 : {U64, U64} = CallByName Test.3 Test.10;
+    ret Test.9;

crates/compiler/test_mono/generated/record_as_pattern_in_closure_arg.txt

@@ -0,0 +1,17 @@
+procedure Test.2 (Test.9):
+    let Test.7 : I64 = StructAtIndex 2 Test.9;
+    let Test.8 : I64 = StructAtIndex 3 Test.9;
+    let Test.17 : {I64, I64, I64, I64} = CallByName Test.2 Test.9;
+    let Test.10 : I64 = StructAtIndex 0 Test.17;
+    let Test.11 : I64 = StructAtIndex 1 Test.17;
+    let Test.16 : {I64, I64, I64, I64} = Struct {Test.7, Test.8, Test.10, Test.11};
+    ret Test.16;
+
+procedure Test.0 ():
+    let Test.18 : I64 = 4i64;
+    let Test.19 : I64 = 3i64;
+    let Test.20 : I64 = 1i64;
+    let Test.21 : I64 = 2i64;
+    let Test.14 : {I64, I64, I64, I64} = Struct {Test.18, Test.19, Test.20, Test.21};
+    let Test.13 : {I64, I64, I64, I64} = CallByName Test.2 Test.14;
+    ret Test.13;

crates/compiler/test_mono/src/tests.rs

@@ -658,15 +658,27 @@ fn record_optional_field_function_use_default() {
 }
 
 #[mono_test]
-fn as_pattern_in_closure_arg() {
+fn record_as_pattern_in_closure_arg() {
     r"
-    g = \{x, y, w, h} -> (x + w, y + h)
+    f = \{x, y, w, h} -> (x + w, y + h)
 
-    f = \({ x, y } as box) ->
+    g = \({ x, y } as box) ->
         (right, bottom) = g box
         (x, y, right, bottom)
 
-    f { x: 1, y: 2, w: 3, h: 4 }
+    g { x: 1, y: 2, w: 3, h: 4 }
+    "
+}
+
+#[mono_test]
+fn opaque_as_pattern_in_closure_arg() {
+    r"
+    Opaque := U64
+
+    f = \(@Opaque x) -> x * 2
+    g = \(@Opaque x as s) -> (x, f s)
+
+    g (@Opaque 42)
     "
 }