diff --git a/example/opt/README.md b/example/opt/README.md
index 3e99ce29a..501b3150d 100644
--- a/example/opt/README.md
+++ b/example/opt/README.md
@@ -339,7 +339,6 @@ Owi is able to get rid of most of the code:
 ```sh
 $ owi opt useless.wat
 (module
-
   (type (sub final  (func)))
   (func $i32binop
 
diff --git a/example/wasm2wat/README.md b/example/wasm2wat/README.md
index 655f7ebc0..16ff8efd7 100644
--- a/example/wasm2wat/README.md
+++ b/example/wasm2wat/README.md
@@ -7,7 +7,6 @@ Given a file `42.wasm`:
 ```sh
 $ owi wasm2wat ./42.wasm
 (module
-
   (type (sub final  (func)))
   (func
     i32.const 20
diff --git a/test/fmt/print.t b/test/fmt/print.t
index 0b8d75e39..02315233c 100644
--- a/test/fmt/print.t
+++ b/test/fmt/print.t
@@ -17,9 +17,7 @@ print symbolic:
 print simplified:
   $ dune exec -- ./print_simplified.exe m.wat
   (module
-    
     (type (sub final  (func (param $x i32) (param $y i32) (result i32))))
-    
     (type (sub final  (func)))
     (func $f (param $x i32) (param $y i32) (result i32)
       local.get 0
diff --git a/test/fmt/script.t b/test/fmt/script.t
index 99f54792d..75a213da0 100644
--- a/test/fmt/script.t
+++ b/test/fmt/script.t
@@ -697,7 +697,6 @@ print script:
       (func $f (param i32) (result i32)
         local.get 0
       )
-      
       (type $sig (sub final  (func (param i32) (result i32))))
       (table 1 1 (ref null func))
       (elem (offset i32.const 0) (ref null func) (item ref.func $f))
@@ -1075,7 +1074,6 @@ print script:
       (func $f (param i32) (result i32)
         local.get 0
       )
-      
       (type $sig (sub final  (func (param i32) (result i32))))
       (table 1 1 (ref null func))
       (elem (offset i32.const 0) (ref null func) (item ref.func $f))
@@ -1094,7 +1092,6 @@ print script:
       (func $f (param i32) (result i32)
         local.get 0
       )
-      
       (type $sig (sub final  (func (param i32) (result i32))))
       (table 1 1 (ref null func))
       (elem (offset i32.const 0) (ref null func) (item ref.func $f))
diff --git a/test/opt/binop.t b/test/opt/binop.t
index 25b55a21f..26804eb26 100644
--- a/test/opt/binop.t
+++ b/test/opt/binop.t
@@ -2,7 +2,6 @@ binary operations instructions:
   $ owi opt binop.wat > binop.opt.wat
   $ cat binop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $i32binop
       
diff --git a/test/opt/block_loop.t b/test/opt/block_loop.t
index 884d40af9..1d6438b8a 100644
--- a/test/opt/block_loop.t
+++ b/test/opt/block_loop.t
@@ -2,7 +2,6 @@ block loop instructions:
   $ owi opt block_loop.wat > block_loop.opt.wat
   $ cat block_loop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/br.t b/test/opt/br.t
index f1e207f7d..d9d7bc921 100644
--- a/test/opt/br.t
+++ b/test/opt/br.t
@@ -2,7 +2,6 @@ br instructions:
   $ owi opt br.wat > br.opt.wat
   $ cat br.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $br
       i32.const 42
diff --git a/test/opt/convert.t b/test/opt/convert.t
index 6def7405d..1318b8b69 100644
--- a/test/opt/convert.t
+++ b/test/opt/convert.t
@@ -2,7 +2,6 @@ f**.convert_i** instructions:
   $ owi opt convert.wat > convert.opt.wat
   $ cat convert.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/debug.t b/test/opt/debug.t
index be822f59b..f8724e722 100644
--- a/test/opt/debug.t
+++ b/test/opt/debug.t
@@ -8,7 +8,6 @@ test debug printing:
   typechecking ...
   optimizing   ...
   (module
-    
     (type (sub final  (func)))
     (global $g i32 i32.const 0)
     (func $start
diff --git a/test/opt/demote_promote.t b/test/opt/demote_promote.t
index b12061425..048eb4eb5 100644
--- a/test/opt/demote_promote.t
+++ b/test/opt/demote_promote.t
@@ -2,7 +2,6 @@ f32.demote_f64 f64.promote_f32 instructions:
   $ owi opt demote_promote.wat > demote_promote.opt.wat
   $ cat demote_promote.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/drop.t b/test/opt/drop.t
index 1a5e2eca7..bdb97b91e 100644
--- a/test/opt/drop.t
+++ b/test/opt/drop.t
@@ -2,7 +2,6 @@ drop instruction:
   $ owi opt drop.wat > drop.opt.wat
   $ cat drop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (global $g i32 i32.const 0)
     (func $start
diff --git a/test/opt/extend_wrap.t b/test/opt/extend_wrap.t
index 0c706d8b2..206dfe8f8 100644
--- a/test/opt/extend_wrap.t
+++ b/test/opt/extend_wrap.t
@@ -2,7 +2,6 @@ i**.extend_** i32.wrap_i64 instructions:
   $ owi opt extend_wrap.wat > extend_wrap.opt.wat
   $ cat extend_wrap.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $extend
       
diff --git a/test/opt/fbinop.t b/test/opt/fbinop.t
index c80c0b11b..49f2056eb 100644
--- a/test/opt/fbinop.t
+++ b/test/opt/fbinop.t
@@ -2,7 +2,6 @@ f32 / f64 binary operations:
   $ owi opt fbinop.wat > fbinop.opt.wat
   $ cat fbinop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/ibinop.t b/test/opt/ibinop.t
index 137ed1723..878f313b6 100644
--- a/test/opt/ibinop.t
+++ b/test/opt/ibinop.t
@@ -2,7 +2,6 @@ i32 / i64 binary operations:
   $ owi opt ibinop.wat > ibinop.opt.wat
   $ cat ibinop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/if.t b/test/opt/if.t
index a7a76dd9e..7b87c4203 100644
--- a/test/opt/if.t
+++ b/test/opt/if.t
@@ -2,9 +2,7 @@ if then else instruction:
   $ owi opt if.wat > if.opt.wat
   $ cat if.opt.wat
   (module
-    
     (type (sub final  (func)))
-    
     (type (sub final  (func (result i32))))
     (func $start
       (block (result i32)
diff --git a/test/opt/local.t b/test/opt/local.t
index b96d9c531..23ce6b435 100644
--- a/test/opt/local.t
+++ b/test/opt/local.t
@@ -2,7 +2,6 @@ unused local variables:
   $ owi opt local.wat > local.opt.wat
   $ cat local.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $f0 (local i32)
       i32.const 0
diff --git a/test/opt/ref_nop.t b/test/opt/ref_nop.t
index 065c973a8..273e478d9 100644
--- a/test/opt/ref_nop.t
+++ b/test/opt/ref_nop.t
@@ -2,7 +2,6 @@ ref.null ref.is_null nop instructions:
   $ owi opt ref_nop.wat > ref_nop.opt.wat
   $ cat ref_nop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/reinterpret.t b/test/opt/reinterpret.t
index ca5f711b9..cf90b6a76 100644
--- a/test/opt/reinterpret.t
+++ b/test/opt/reinterpret.t
@@ -2,7 +2,6 @@ f**.reinterpret_i** i**.reinterpret_f** instructions:
   $ owi opt reinterpret.wat > reinterpret.opt.wat
   $ cat reinterpret.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/relop_testop.t b/test/opt/relop_testop.t
index 1d9ee1d2a..a6921708c 100644
--- a/test/opt/relop_testop.t
+++ b/test/opt/relop_testop.t
@@ -2,7 +2,6 @@
   $ owi opt relop_testop.wat > relop_testop.opt.wat
   $ cat relop_testop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $i32relop
       
diff --git a/test/opt/return.t b/test/opt/return.t
index 70d9969d1..4de77cd62 100644
--- a/test/opt/return.t
+++ b/test/opt/return.t
@@ -2,9 +2,7 @@ return instructions:
   $ owi opt return.wat > return.opt.wat
   $ cat return.opt.wat
   (module
-    
     (type (sub final  (func (result i32))))
-    
     (type (sub final  (func)))
     (table $tab 1 1 (ref null func))
     (func $return (result i32)
diff --git a/test/opt/select.t b/test/opt/select.t
index 8af957676..f03c920a8 100644
--- a/test/opt/select.t
+++ b/test/opt/select.t
@@ -2,7 +2,6 @@ select instruction:
   $ owi opt select.wat > select.opt.wat
   $ cat select.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start
       
diff --git a/test/opt/tee.t b/test/opt/tee.t
index aff865e69..a7ed45d07 100644
--- a/test/opt/tee.t
+++ b/test/opt/tee.t
@@ -2,7 +2,6 @@ set get tee simplification:
   $ owi opt tee.wat > tee.opt.wat
   $ cat tee.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $start (local $x i32)
       i32.const 41
diff --git a/test/opt/trunc.t b/test/opt/trunc.t
index 6ebadfee1..76f24bf9c 100644
--- a/test/opt/trunc.t
+++ b/test/opt/trunc.t
@@ -2,7 +2,6 @@
   $ owi opt trunc.wat > trunc.opt.wat
   $ cat trunc.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $trunc
       
diff --git a/test/opt/unop.t b/test/opt/unop.t
index 5395c9c20..168701d83 100644
--- a/test/opt/unop.t
+++ b/test/opt/unop.t
@@ -2,7 +2,6 @@ unop () instructions:
   $ owi opt unop.wat > unop.opt.wat
   $ cat unop.opt.wat
   (module
-    
     (type (sub final  (func)))
     (func $iunop
       
diff --git a/test/wasm2wat/done.t b/test/wasm2wat/done.t
index 4b154995b..c94eeb281 100644
--- a/test/wasm2wat/done.t
+++ b/test/wasm2wat/done.t
@@ -1,8 +1,6 @@
   $ owi wasm2wat done.wasm
   (module
-    
     (type (sub final  (func (param i32) (param i32) (result i32))))
-    
     (type (sub final  (func)))
     (func (param i32) (param i32) (result i32)
       local.get 0
diff --git a/test/wasm2wat/emit.t b/test/wasm2wat/emit.t
index 1783c8452..ffe169a48 100644
--- a/test/wasm2wat/emit.t
+++ b/test/wasm2wat/emit.t
@@ -2,9 +2,7 @@ test that we can emit to a file:
   $ owi wasm2wat m.wasm --emit-file
   $ cat m.wat
   (module
-    
     (type (sub final  (func (param i32) (param i32) (result i32))))
-    
     (type (sub final  (func)))
     (func (param i32) (param i32) (result i32)
       local.get 0
diff --git a/test/wasm2wat/locals.t b/test/wasm2wat/locals.t
index 5e4328487..047a60c85 100644
--- a/test/wasm2wat/locals.t
+++ b/test/wasm2wat/locals.t
@@ -1,8 +1,6 @@
   $ owi wasm2wat locals.wasm
   (module
-    
     (type (sub final  (func (param i32) (param i32) (param i32))))
-    
     (type (sub final  (func)))
     (func (param i32) (param i32) (param i32) (local i32) (local i32)
       local.get 3
diff --git a/test/wasm2wat/locals_drop.t b/test/wasm2wat/locals_drop.t
index 02d999c5d..0d2bb0233 100644
--- a/test/wasm2wat/locals_drop.t
+++ b/test/wasm2wat/locals_drop.t
@@ -1,8 +1,6 @@
   $ owi wasm2wat locals_drop.wasm
   (module
-    
     (type (sub final  (func (param i32) (param i32) (param i32))))
-    
     (type (sub final  (func)))
     (func (param i32) (param i32) (param i32) (local i32) (local i32)
       local.get 3
diff --git a/test/wasm2wat/print.t b/test/wasm2wat/print.t
index bc44a97fc..8fe73c3bb 100644
--- a/test/wasm2wat/print.t
+++ b/test/wasm2wat/print.t
@@ -1,9 +1,7 @@
 print symbolic:
   $ owi wasm2wat m.wasm
   (module
-    
     (type (sub final  (func (param i32) (param i32) (result i32))))
-    
     (type (sub final  (func)))
     (func (param i32) (param i32) (result i32)
       local.get 0
diff --git a/test/wat2wasm/block_type1.t b/test/wat2wasm/block_type1.t
new file mode 100644
index 000000000..2d2aa0349
--- /dev/null
+++ b/test/wat2wasm/block_type1.t
@@ -0,0 +1,16 @@
+  $ owi wat2wasm block_type1.wat
+  $ owi wasm2wat block_type1.wasm
+  (module
+    (type (sub final  (func)))
+    (type (sub final  (func (param i32) (result i32))))
+    (func
+      i32.const 1
+      (block (param i32) (result i32)
+        i32.const 1
+        i32.add)
+      drop
+    )
+    (start 0)
+  )
+  $ owi sym block_type1.wasm
+  All OK
diff --git a/test/wat2wasm/block_type1.wat b/test/wat2wasm/block_type1.wat
new file mode 100644
index 000000000..fb7a0461b
--- /dev/null
+++ b/test/wat2wasm/block_type1.wat
@@ -0,0 +1,11 @@
+(module
+  (func
+    i32.const 1
+    (block (param i32) (result i32)
+      i32.const 1
+      i32.add
+    )
+    drop
+  )
+  (start 0)
+)
diff --git a/test/wat2wasm/block_type2.t b/test/wat2wasm/block_type2.t
new file mode 100644
index 000000000..7fd1ccfa9
--- /dev/null
+++ b/test/wat2wasm/block_type2.t
@@ -0,0 +1,26 @@
+  $ owi wat2wasm block_type2.wat
+  $ owi wasm2wat block_type2.wasm
+  (module
+    (type (sub final  (func (result i32))))
+    (type (sub final  (func (param i32) (result i32))))
+    (type (sub final  (func)))
+    (func (result i32) (local i32)
+      i32.const 0
+      local.tee 0
+      (loop (param i32) (result i32)
+        i32.const 1
+        i32.add
+        local.tee 0
+        local.get 0
+        i32.const 10
+        i32.le_s
+        br_if 0)
+    )
+    (func
+      call 0
+      drop
+    )
+    (start 1)
+  )
+  $ owi sym block_type2.wasm
+  All OK
diff --git a/test/wat2wasm/block_type2.wat b/test/wat2wasm/block_type2.wat
new file mode 100644
index 000000000..e06ba4023
--- /dev/null
+++ b/test/wat2wasm/block_type2.wat
@@ -0,0 +1,21 @@
+(module
+  (func (result i32)
+    (local i32)
+    i32.const 0
+    local.tee 0
+    (loop (param i32) (result i32)
+      i32.const 1
+      i32.add
+      local.tee 0
+      local.get 0
+      i32.const 10
+      i32.le_s
+      br_if 0
+    )
+  )
+  (func
+    call 0
+    drop
+  )
+  (start 1)
+)
diff --git a/test/wat2wasm/call_indirect.t b/test/wat2wasm/call_indirect.t
index f68677f75..08721ffd2 100644
--- a/test/wat2wasm/call_indirect.t
+++ b/test/wat2wasm/call_indirect.t
@@ -37,9 +37,7 @@
   stack        : [  ]
   $ owi wasm2wat call_indirect.wasm
   (module
-    
     (type (sub final  (func (param i64) (result i64))))
-    
     (type (sub final  (func)))
     (table 1 10 (ref null func))
     (func (param i64) (result i64)
diff --git a/test/wat2wasm/cmd_conc.t b/test/wat2wasm/cmd_conc.t
index 88d880fd4..d520a94f3 100644
--- a/test/wat2wasm/cmd_conc.t
+++ b/test/wat2wasm/cmd_conc.t
@@ -9,9 +9,7 @@
   $ owi wasm2wat symbolic.wasm
   (module
     (import "symbolic" "i32_symbol" (func  (result i32)))
-    
     (type (sub final  (func (result i32))))
-    
     (type (sub final  (func)))
     (func (local i32)
       call 0
diff --git a/test/wat2wasm/cmd_sym.t b/test/wat2wasm/cmd_sym.t
index 01e34ffd5..c1b334620 100644
--- a/test/wat2wasm/cmd_sym.t
+++ b/test/wat2wasm/cmd_sym.t
@@ -9,9 +9,7 @@
   $ owi wasm2wat symbolic.wasm
   (module
     (import "symbolic" "i32_symbol" (func  (result i32)))
-    
     (type (sub final  (func (result i32))))
-    
     (type (sub final  (func)))
     (func (local i32)
       call 0
diff --git a/test/wat2wasm/dune b/test/wat2wasm/dune
index d303e2189..b0572686f 100644
--- a/test/wat2wasm/dune
+++ b/test/wat2wasm/dune
@@ -2,6 +2,8 @@
  (deps
   %{bin:owi}
   bad.ext
+  block_type1.wat
+  block_type2.wat
   call_indirect.wat
   func.wat
   globals.wat
diff --git a/test/wat2wasm/func.t b/test/wat2wasm/func.t
index 06e141867..020146768 100644
--- a/test/wat2wasm/func.t
+++ b/test/wat2wasm/func.t
@@ -26,9 +26,7 @@
   stack        : [  ]
   $ owi wasm2wat func.wasm
   (module
-    
     (type (sub final  (func (param f32) (result f32))))
-    
     (type (sub final  (func)))
     (func (param f32) (result f32) (local f32)
       f32.const 2.019_999_980_926_513_7
diff --git a/test/wat2wasm/globals.t b/test/wat2wasm/globals.t
index 5218a1e75..2b838aa25 100644
--- a/test/wat2wasm/globals.t
+++ b/test/wat2wasm/globals.t
@@ -22,7 +22,6 @@
   stack        : [  ]
   $ owi wasm2wat globals.wasm
   (module
-    
     (type (sub final  (func)))
     (global i32 i32.const 42)
     (global (mut i64) i64.const 2)
diff --git a/test/wat2wasm/loop.t b/test/wat2wasm/loop.t
index 5028eafd0..93fb655e2 100644
--- a/test/wat2wasm/loop.t
+++ b/test/wat2wasm/loop.t
@@ -112,11 +112,8 @@
   stack        : [  ]
   $ owi wasm2wat loop.wasm
   (module
-    
     (type (sub final  (func (param i32) (result i64))))
-    
     (type (sub final  (func (result i64))))
-    
     (type (sub final  (func)))
     (func (param i32) (result i64) (local i32)
       i32.const 0
diff --git a/test/wat2wasm/mem.t b/test/wat2wasm/mem.t
index 5aa5d59f6..7e8548a58 100644
--- a/test/wat2wasm/mem.t
+++ b/test/wat2wasm/mem.t
@@ -2,15 +2,10 @@
   $ owi run mem.wasm
   $ owi wasm2wat mem.wasm
   (module
-    
     (type (sub final  (func)))
-    
     (type (sub final  (func (param i32) (param i32))))
-    
     (type (sub final  (func (param i32) (param i64))))
-    
     (type (sub final  (func (param i32) (param f32))))
-    
     (type (sub final  (func (param i32) (param f64))))
     (memory 1)
     (func
diff --git a/test/wat2wasm/rec.t b/test/wat2wasm/rec.t
index fc9b47c80..f225d885c 100644
--- a/test/wat2wasm/rec.t
+++ b/test/wat2wasm/rec.t
@@ -2,9 +2,7 @@
   $ owi run rec.wasm
   $ owi wasm2wat rec.wasm
   (module
-    
     (type (sub final  (func (param i32) (result i32))))
-    
     (type (sub final  (func)))
     (memory 1)
     (func (param i32) (result i32)