[NFC] Add the type of the Expression when eliding it (#6362)

In some cases we don't print an Expression in full if it is unreachable, so
we print something instead as a placeholder. This happens in unreachable
code when the children don't provide enough info to print the parent (e.g.
a StructGet with an unreachable reference doesn't know what struct type
to use).

This PR prints out the name of the Expression type of such things, which
can help debugging sometimes. 

30 files changed, 69 insertions, 68 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 2288b6914..abe68f13d 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -2786,7 +2786,8 @@ void PrintSExpression::maybePrintUnreachableReplacement(Expression* curr,
   // Emit a block with drops of the children.
   o << "(block";
   if (!minify) {
-    o << " ;; (replaces something unreachable we can't emit)";
+    o << " ;; (replaces unreachable " << getExpressionName(curr)
+      << " we can't emit)";
   }
   incIndent();
   for (auto* child : ChildIterator(curr)) {
diff --git a/test/lit/passes/cfp.wast b/test/lit/passes/cfp.wast
index c84eea900..44e929439 100644
--- a/test/lit/passes/cfp.wast
+++ b/test/lit/passes/cfp.wast
@@ -508,7 +508,7 @@
 
   ;; CHECK:      (func $test (type $0)
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
@@ -516,14 +516,14 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/dae-gc-refine-return.wast b/test/lit/passes/dae-gc-refine-return.wast
index 24ad4e61b..8e54a538e 100644
--- a/test/lit/passes/dae-gc-refine-return.wast
+++ b/test/lit/passes/dae-gc-refine-return.wast
@@ -472,7 +472,7 @@
   (return_call_ref $"return_{}" (local.get $"return_{}"))
  )
  ;; CHECK:      (func $tail-caller-call_ref-unreachable (type $2) (result anyref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/dae_all-features.wast b/test/lit/passes/dae_all-features.wast
index 17626c953..d4390351f 100644
--- a/test/lit/passes/dae_all-features.wast
+++ b/test/lit/passes/dae_all-features.wast
@@ -699,7 +699,7 @@
  ;; CHECK:      (type $1 (func))
 
  ;; CHECK:      (func $no-caller (type $A) (result (ref $A))
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (ref.null nofunc)
  ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/gsi.wast b/test/lit/passes/gsi.wast
index 70991f550..f60e911c7 100644
--- a/test/lit/passes/gsi.wast
+++ b/test/lit/passes/gsi.wast
@@ -1208,7 +1208,7 @@
   ))
 
   ;; CHECK:      (func $func (type $1) (param $ref (ref null $A)) (result i32)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (ref.null none)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/gto-removals.wast b/test/lit/passes/gto-removals.wast
index 558b0c85f..d49ab1201 100644
--- a/test/lit/passes/gto-removals.wast
+++ b/test/lit/passes/gto-removals.wast
@@ -560,7 +560,7 @@
 
   ;; CHECK:      (func $new-unreachable (type $4)
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (i32.const 2)
   ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/gufa-extern.wast b/test/lit/passes/gufa-extern.wast
index 6b2872488..7cc604c76 100644
--- a/test/lit/passes/gufa-extern.wast
+++ b/test/lit/passes/gufa-extern.wast
@@ -39,7 +39,7 @@
 
   ;; CHECK:      (func $non-exported (type $0) (param $ext externref) (param $any anyref)
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable RefCast we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (extern.internalize
   ;; CHECK-NEXT:      (unreachable)
diff --git a/test/lit/passes/gufa-refs.wast b/test/lit/passes/gufa-refs.wast
index c2c9564ad..e6e5d0bde 100644
--- a/test/lit/passes/gufa-refs.wast
+++ b/test/lit/passes/gufa-refs.wast
@@ -4567,7 +4567,7 @@
   )
 
   ;; CHECK:      (func $call_ref-nofunc (type $2)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (i32.const 1)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/gufa-tnh-closed.wast b/test/lit/passes/gufa-tnh-closed.wast
index 790663af4..b55ae5ea6 100644
--- a/test/lit/passes/gufa-tnh-closed.wast
+++ b/test/lit/passes/gufa-tnh-closed.wast
@@ -38,7 +38,7 @@
   )
 
   ;; CHECK:      (func $caller (type $2) (param $x funcref)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
@@ -83,7 +83,7 @@
   )
 
   ;; CHECK:      (func $caller (type $0) (param $x funcref)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
@@ -496,7 +496,7 @@
   ;; CHECK-NEXT:    (local.get $func3)
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (struct.new_default $Y2)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/gufa-vs-cfp.wast b/test/lit/passes/gufa-vs-cfp.wast
index eb95c6bed..44a44a3e5 100644
--- a/test/lit/passes/gufa-vs-cfp.wast
+++ b/test/lit/passes/gufa-vs-cfp.wast
@@ -459,7 +459,7 @@
 
   ;; CHECK:      (func $test (type $0)
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (i32.const 10)
   ;; CHECK-NEXT:    )
@@ -469,9 +469,9 @@
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; CHECK-NEXT:   (drop
-  ;; CHECK-NEXT:    (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:    (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:     (drop
   ;; CHECK-NEXT:      (unreachable)
   ;; CHECK-NEXT:     )
diff --git a/test/lit/passes/heap2local.wast b/test/lit/passes/heap2local.wast
index 286bfdc19..b693c49ee 100644
--- a/test/lit/passes/heap2local.wast
+++ b/test/lit/passes/heap2local.wast
@@ -215,9 +215,9 @@
 
   ;; CHECK:      (func $ignore-unreachable (type $1)
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:    (drop
-  ;; CHECK-NEXT:     (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:     (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:      (drop
   ;; CHECK-NEXT:       (i32.const 2)
   ;; CHECK-NEXT:      )
diff --git a/test/lit/passes/inlining-optimizing.wast b/test/lit/passes/inlining-optimizing.wast
index 870978e75..86553174d 100644
--- a/test/lit/passes/inlining-optimizing.wast
+++ b/test/lit/passes/inlining-optimizing.wast
@@ -13,7 +13,7 @@
  )
  ;; CHECK:      (func $1 (type $none_=>_none)
  ;; CHECK-NEXT:  (drop
- ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:   (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:    (drop
  ;; CHECK-NEXT:     (unreachable)
  ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/inlining_vacuum_optimize-instructions.wast b/test/lit/passes/inlining_vacuum_optimize-instructions.wast
index f93dca217..db681ef69 100644
--- a/test/lit/passes/inlining_vacuum_optimize-instructions.wast
+++ b/test/lit/passes/inlining_vacuum_optimize-instructions.wast
@@ -19,7 +19,7 @@
 
  ;; CHECK:      (func $target (type $2) (param $0 (ref null $A))
  ;; CHECK-NEXT:  (drop
- ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:   (block ;; (replaces unreachable RefCast we can't emit)
  ;; CHECK-NEXT:    (drop
  ;; CHECK-NEXT:     (unreachable)
  ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/local-subtyping.wast b/test/lit/passes/local-subtyping.wast
index b25bb41b1..582c24f23 100644
--- a/test/lit/passes/local-subtyping.wast
+++ b/test/lit/passes/local-subtyping.wast
@@ -276,7 +276,7 @@
   ;; CHECK-NEXT:   (ref.null nofunc)
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (local.set $x
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (local.get $f)
   ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/optimize-instructions-call_ref.wast b/test/lit/passes/optimize-instructions-call_ref.wast
index f83ddb091..5e6c3b48a 100644
--- a/test/lit/passes/optimize-instructions-call_ref.wast
+++ b/test/lit/passes/optimize-instructions-call_ref.wast
@@ -158,7 +158,7 @@
  )
 
  ;; CHECK:      (func $fallthrough-bad-type (type $none_=>_i32) (result i32)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (block (result (ref nofunc))
  ;; CHECK-NEXT:     (drop
@@ -213,7 +213,7 @@
  )
 
  ;; CHECK:      (func $ignore-unreachable (type $none_=>_none)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/optimize-instructions-gc-heap.wast b/test/lit/passes/optimize-instructions-gc-heap.wast
index 5af517bfe..137105468 100644
--- a/test/lit/passes/optimize-instructions-gc-heap.wast
+++ b/test/lit/passes/optimize-instructions-gc-heap.wast
@@ -713,7 +713,7 @@
   ;; CHECK:      (func $unreachable (type $1)
   ;; CHECK-NEXT:  (local $ref (ref null $struct))
   ;; CHECK-NEXT:  (local.tee $ref
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/optimize-instructions-gc-iit.wast b/test/lit/passes/optimize-instructions-gc-iit.wast
index 1cd92d98a..df225a8c7 100644
--- a/test/lit/passes/optimize-instructions-gc-iit.wast
+++ b/test/lit/passes/optimize-instructions-gc-iit.wast
@@ -110,7 +110,7 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable RefCast we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
@@ -126,7 +126,7 @@
   ;; TNH-NEXT:   )
   ;; TNH-NEXT:  )
   ;; TNH-NEXT:  (drop
-  ;; TNH-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; TNH-NEXT:   (block ;; (replaces unreachable RefCast we can't emit)
   ;; TNH-NEXT:    (drop
   ;; TNH-NEXT:     (unreachable)
   ;; TNH-NEXT:    )
diff --git a/test/lit/passes/optimize-instructions-gc-tnh.wast b/test/lit/passes/optimize-instructions-gc-tnh.wast
index 3cf7a72d2..ff2975766 100644
--- a/test/lit/passes/optimize-instructions-gc-tnh.wast
+++ b/test/lit/passes/optimize-instructions-gc-tnh.wast
@@ -497,7 +497,7 @@
   )
 
   ;; TNH:      (func $null.arm.null.effects (type $void)
-  ;; TNH-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; TNH-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; TNH-NEXT:   (drop
   ;; TNH-NEXT:    (select
   ;; TNH-NEXT:     (unreachable)
@@ -523,7 +523,7 @@
   ;; TNH-NEXT:  )
   ;; TNH-NEXT: )
   ;; NO_TNH:      (func $null.arm.null.effects (type $void)
-  ;; NO_TNH-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; NO_TNH-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; NO_TNH-NEXT:   (drop
   ;; NO_TNH-NEXT:    (select
   ;; NO_TNH-NEXT:     (unreachable)
@@ -904,7 +904,7 @@
   )
 
   ;; TNH:      (func $select.unreachable.child (type $6) (param $x (ref $struct)) (result (ref $struct))
-  ;; TNH-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; TNH-NEXT:  (block ;; (replaces unreachable RefCast we can't emit)
   ;; TNH-NEXT:   (drop
   ;; TNH-NEXT:    (unreachable)
   ;; TNH-NEXT:   )
@@ -912,7 +912,7 @@
   ;; TNH-NEXT:  )
   ;; TNH-NEXT: )
   ;; NO_TNH:      (func $select.unreachable.child (type $6) (param $x (ref $struct)) (result (ref $struct))
-  ;; NO_TNH-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; NO_TNH-NEXT:  (block ;; (replaces unreachable RefCast we can't emit)
   ;; NO_TNH-NEXT:   (drop
   ;; NO_TNH-NEXT:    (unreachable)
   ;; NO_TNH-NEXT:   )
diff --git a/test/lit/passes/optimize-instructions-gc.wast b/test/lit/passes/optimize-instructions-gc.wast
index 9a27926c8..9a49c3435 100644
--- a/test/lit/passes/optimize-instructions-gc.wast
+++ b/test/lit/passes/optimize-instructions-gc.wast
@@ -286,7 +286,7 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable RefCast we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
@@ -2773,7 +2773,7 @@
 
   ;; CHECK:      (func $struct.set.null.fallthrough (type $5)
   ;; CHECK-NEXT:  (local $temp (ref null $struct))
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (local.tee $temp
   ;; CHECK-NEXT:     (unreachable)
@@ -2802,7 +2802,7 @@
 
   ;; CHECK:      (func $set.array.null (type $5)
   ;; CHECK-NEXT:  (local $temp (ref none))
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable ArraySet we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (local.tee $temp
   ;; CHECK-NEXT:     (unreachable)
diff --git a/test/lit/passes/precompute-gc-immutable.wast b/test/lit/passes/precompute-gc-immutable.wast
index a3bef210f..7520c8f12 100644
--- a/test/lit/passes/precompute-gc-immutable.wast
+++ b/test/lit/passes/precompute-gc-immutable.wast
@@ -176,7 +176,7 @@
   ;; CHECK:      (func $unreachable (type $2)
   ;; CHECK-NEXT:  (local $ref-imm (ref null $struct-imm))
   ;; CHECK-NEXT:  (local.tee $ref-imm
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
@@ -223,7 +223,7 @@
   ;; CHECK:      (func $local-null (type $2)
   ;; CHECK-NEXT:  (local $ref-imm (ref null $struct-imm))
   ;; CHECK-NEXT:  (call $helper
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (ref.null none)
   ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/precompute-gc.wast b/test/lit/passes/precompute-gc.wast
index 824587df9..2b16cb43f 100644
--- a/test/lit/passes/precompute-gc.wast
+++ b/test/lit/passes/precompute-gc.wast
@@ -750,7 +750,7 @@
  ;; CHECK-NEXT:   (ref.null none)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT:  (drop
- ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
  ;; CHECK-NEXT:    (drop
  ;; CHECK-NEXT:     (ref.null none)
  ;; CHECK-NEXT:    )
@@ -787,7 +787,7 @@
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT:  (drop
- ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
  ;; CHECK-NEXT:    (drop
  ;; CHECK-NEXT:     (ref.null none)
  ;; CHECK-NEXT:    )
@@ -851,7 +851,7 @@
  )
 
  ;; CHECK:      (func $new_block_unreachable (type $8) (result anyref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable StructNew we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (block
  ;; CHECK-NEXT:     (unreachable)
diff --git a/test/lit/passes/remove-unused-brs-gc.wast b/test/lit/passes/remove-unused-brs-gc.wast
index 84c16cab2..9dc871e32 100644
--- a/test/lit/passes/remove-unused-brs-gc.wast
+++ b/test/lit/passes/remove-unused-brs-gc.wast
@@ -602,7 +602,7 @@
  ;; CHECK:      (func $fallthrough-unreachable (type $6) (param $0 i31ref) (result anyref)
  ;; CHECK-NEXT:  (block $outer
  ;; CHECK-NEXT:   (drop
- ;; CHECK-NEXT:    (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:    (block ;; (replaces unreachable RefCast we can't emit)
  ;; CHECK-NEXT:     (drop
  ;; CHECK-NEXT:      (block
  ;; CHECK-NEXT:       (drop
diff --git a/test/lit/passes/remove-unused-module-elements-refs.wast b/test/lit/passes/remove-unused-module-elements-refs.wast
index 44c87fefc..146a25ea6 100644
--- a/test/lit/passes/remove-unused-module-elements-refs.wast
+++ b/test/lit/passes/remove-unused-module-elements-refs.wast
@@ -50,7 +50,7 @@
   ;; CHECK-NEXT:  (call_ref $A
   ;; CHECK-NEXT:   (local.get $A)
   ;; CHECK-NEXT:  )
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
@@ -80,7 +80,7 @@
   ;; OPEN_WORLD-NEXT:  (call_ref $A
   ;; OPEN_WORLD-NEXT:   (local.get $A)
   ;; OPEN_WORLD-NEXT:  )
-  ;; OPEN_WORLD-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; OPEN_WORLD-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; OPEN_WORLD-NEXT:   (drop
   ;; OPEN_WORLD-NEXT:    (unreachable)
   ;; OPEN_WORLD-NEXT:   )
@@ -810,7 +810,7 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
@@ -871,7 +871,7 @@
   ;; OPEN_WORLD-NEXT:   )
   ;; OPEN_WORLD-NEXT:  )
   ;; OPEN_WORLD-NEXT:  (drop
-  ;; OPEN_WORLD-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; OPEN_WORLD-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; OPEN_WORLD-NEXT:    (drop
   ;; OPEN_WORLD-NEXT:     (unreachable)
   ;; OPEN_WORLD-NEXT:    )
diff --git a/test/lit/passes/signature-pruning.wast b/test/lit/passes/signature-pruning.wast
index cf6485f63..4d22ef619 100644
--- a/test/lit/passes/signature-pruning.wast
+++ b/test/lit/passes/signature-pruning.wast
@@ -819,7 +819,7 @@
 
   ;; CHECK:      (func $0 (type $0)
   ;; CHECK-NEXT:  (local $0 f32)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable RefCast we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/signature-refining.wast b/test/lit/passes/signature-refining.wast
index 7b4b7921e..215c4e9c4 100644
--- a/test/lit/passes/signature-refining.wast
+++ b/test/lit/passes/signature-refining.wast
@@ -856,7 +856,7 @@
   (type $F (func))
 
   ;; CHECK:      (func $func (type $F)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (ref.null nofunc)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/simplify-locals-gc.wast b/test/lit/passes/simplify-locals-gc.wast
index 98d1f5925..b5b843474 100644
--- a/test/lit/passes/simplify-locals-gc.wast
+++ b/test/lit/passes/simplify-locals-gc.wast
@@ -76,7 +76,7 @@
   ;; CHECK:      (func $unreachable-struct.get (type $6) (param $x (ref $struct)) (param $y (ref $struct-immutable)) (result i32)
   ;; CHECK-NEXT:  (local $temp i32)
   ;; CHECK-NEXT:  (local.tee $temp
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/type-generalizing.wast b/test/lit/passes/type-generalizing.wast
index d97f1c283..2c1714a46 100644
--- a/test/lit/passes/type-generalizing.wast
+++ b/test/lit/passes/type-generalizing.wast
@@ -915,7 +915,7 @@
  ;; CHECK:      (func $call-ref-impossible (type $2) (result eqref)
  ;; CHECK-NEXT:  (local $f nullfuncref)
  ;; CHECK-NEXT:  (local $arg anyref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (local.get $arg)
  ;; CHECK-NEXT:   )
@@ -1044,7 +1044,7 @@
 
  ;; CHECK:      (func $struct-get-impossible (type $0) (result anyref)
  ;; CHECK-NEXT:  (local $var nullref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable StructGet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (local.get $var)
  ;; CHECK-NEXT:   )
@@ -1101,7 +1101,7 @@
  ;; CHECK:      (func $struct-set-impossible (type $3)
  ;; CHECK-NEXT:  (local $ref nullref)
  ;; CHECK-NEXT:  (local $val anyref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (local.get $ref)
  ;; CHECK-NEXT:   )
@@ -1246,7 +1246,7 @@
 
  ;; CHECK:      (func $array-get-impossible (type $3) (result anyref)
  ;; CHECK-NEXT:  (local $val nullref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayGet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (local.get $val)
  ;; CHECK-NEXT:   )
@@ -1289,7 +1289,7 @@
  ;; CHECK:      (func $array-set-impossible (type $0)
  ;; CHECK-NEXT:  (local $ref nullref)
  ;; CHECK-NEXT:  (local $val anyref)
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArraySet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (local.get $ref)
  ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/type-refining.wast b/test/lit/passes/type-refining.wast
index 8ce95c46d..1bddb9776 100644
--- a/test/lit/passes/type-refining.wast
+++ b/test/lit/passes/type-refining.wast
@@ -844,7 +844,7 @@
 
   ;; CHECK:      (func $func (type $6) (param $Leaf1-Outer (ref null $Leaf1-Outer))
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (block
   ;; CHECK-NEXT:      (drop
@@ -1106,7 +1106,7 @@
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (struct.set $struct 0
   ;; CHECK-NEXT:   (local.get $struct)
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructGet we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (block (result nullref)
   ;; CHECK-NEXT:      (ref.null none)
@@ -1196,9 +1196,9 @@
   ;; CHECK:       (type $2 (func))
 
   ;; CHECK:      (func $0 (type $2)
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; CHECK-NEXT:   (drop
-  ;; CHECK-NEXT:    (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:    (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:     (drop
   ;; CHECK-NEXT:      (block
   ;; CHECK-NEXT:       (drop
@@ -1352,7 +1352,7 @@
   )
 
   ;; CHECK:      (func $bottom.type (type $1) (param $ref (ref none)) (param $value (ref noextern))
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (local.get $ref)
   ;; CHECK-NEXT:   )
@@ -1371,7 +1371,7 @@
   )
 
   ;; CHECK:      (func $unreachable (type $0) (param $value (ref noextern))
-  ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
   ;; CHECK-NEXT:   (drop
   ;; CHECK-NEXT:    (unreachable)
   ;; CHECK-NEXT:   )
diff --git a/test/lit/passes/type-ssa.wast b/test/lit/passes/type-ssa.wast
index 37bdef17c..771b4b9ae 100644
--- a/test/lit/passes/type-ssa.wast
+++ b/test/lit/passes/type-ssa.wast
@@ -165,7 +165,7 @@
   ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT:  (drop
-  ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+  ;; CHECK-NEXT:   (block ;; (replaces unreachable StructNew we can't emit)
   ;; CHECK-NEXT:    (drop
   ;; CHECK-NEXT:     (unreachable)
   ;; CHECK-NEXT:    )
diff --git a/test/lit/passes/unsubtyping.wast b/test/lit/passes/unsubtyping.wast
index ad74ab736..8408c2e7d 100644
--- a/test/lit/passes/unsubtyping.wast
+++ b/test/lit/passes/unsubtyping.wast
@@ -936,7 +936,7 @@
  ;; CHECK-NEXT:   (struct.new_default $sub)
  ;; CHECK-NEXT:   (ref.func $call-ref)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (struct.new_default $sub)
  ;; CHECK-NEXT:   )
@@ -945,7 +945,7 @@
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable CallRef we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (struct.new_default $sub)
  ;; CHECK-NEXT:   )
@@ -1122,7 +1122,7 @@
  ;; CHECK-NEXT:  (drop
  ;; CHECK-NEXT:   (struct.new_default $struct)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable StructNew we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
@@ -1165,7 +1165,7 @@
  ;; CHECK-NEXT:   (local.get $struct)
  ;; CHECK-NEXT:   (struct.new_default $sub)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
@@ -1174,7 +1174,7 @@
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable StructSet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (ref.null none)
  ;; CHECK-NEXT:   )
@@ -1229,7 +1229,7 @@
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT:  (drop
- ;; CHECK-NEXT:   (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:   (block ;; (replaces unreachable ArrayNew we can't emit)
  ;; CHECK-NEXT:    (drop
  ;; CHECK-NEXT:     (unreachable)
  ;; CHECK-NEXT:    )
@@ -1287,7 +1287,7 @@
  ;; CHECK-NEXT:    (i32.const 0)
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayNewElem we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
@@ -1332,7 +1332,7 @@
  ;; CHECK-NEXT:    (struct.new_default $sub)
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayNewFixed we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
@@ -1371,7 +1371,7 @@
  ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:   (struct.new_default $sub)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArraySet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (unreachable)
  ;; CHECK-NEXT:   )
@@ -1383,7 +1383,7 @@
  ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block ;; (replaces something unreachable we can't emit)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArraySet we can't emit)
  ;; CHECK-NEXT:   (drop
  ;; CHECK-NEXT:    (ref.null none)
  ;; CHECK-NEXT:   )