add transcript demonstrating 4424

unison-src/transcripts/fix4424.md

@@ -0,0 +1,55 @@
+```ucm:hide
+.> builtins.merge
+```
+
+Some basics:
+
+```unison:hide
+unique type Cat.Dog = Mouse Nat
+unique type Rat.Dog = Bird
+
+countCat = cases
+  Cat.Dog.Mouse x -> Bird
+```
+
+```ucm
+.> add
+```
+
+Now I want to add a constructor.
+
+```unison:hide
+unique type Rat.Dog = Bird | Mouse
+```
+
+```ucm:error
+.> update
+```
+
+Here's the code that `update` produced:
+
+```unison:error
+countCat : Cat.Dog -> Rat.Dog
+countCat = cases Mouse x -> Bird
+
+unique type Rat.Dog = Bird | Mouse
+```
+
+Okay, hmm. TBH I think this code should have type-checked without user intervention, but the way it printed (`cases Mouse x`) is ambiguous, and UCM assumed `Mouse` meant `Rat.Dog.Mouse` instead of `Cat.Dog.Mouse`, which caused parsing to fail.
+
+I'll fix it by making it explicit:
+
+```unison
+countCat : Cat.Dog -> Rat.Dog
+countCat = cases Cat.Dog.Mouse x -> Bird
+
+unique type Rat.Dog = Bird | Mouse
+```
+
+Ok, all set! Now let's update.
+
+```ucm:error
+.> update
+```
+
+Why is it still printing just `Mouse` and failing?

unison-src/transcripts/fix4424.output.md

@@ -0,0 +1,111 @@
+Some basics:
+
+```unison
+unique type Cat.Dog = Mouse Nat
+unique type Rat.Dog = Bird
+
+countCat = cases
+  Cat.Dog.Mouse x -> Bird
+```
+
+```ucm
+.> add
+
+  ⍟ I've added these definitions:
+  
+    unique type Cat.Dog
+    unique type Rat.Dog
+    countCat : Cat.Dog -> Rat.Dog
+
+```
+Now I want to add a constructor.
+
+```unison
+unique type Rat.Dog = Bird | Mouse
+```
+
+```ucm
+.> update
+
+  Okay, I'm searching the branch for code that needs to be
+  updated...
+
+  That's done. Now I'm making sure everything typechecks...
+
+  countCat : Cat.Dog -> Rat.Dog
+  countCat = cases Mouse x -> Bird
+  
+  unique type Rat.Dog = Bird | Mouse
+
+  Typechecking failed. I've updated your scratch file with the
+  definitions that need fixing. Once the file is compiling, try
+  `update` again.
+
+```
+Here's the code that `update` produced:
+
+```unison
+countCat : Cat.Dog -> Rat.Dog
+countCat = cases Mouse x -> Bird
+
+unique type Rat.Dog = Bird | Mouse
+```
+
+```ucm
+
+  This pattern has the wrong number of arguments
+  
+      2 | countCat = cases Mouse x -> Bird
+  
+  The constructor has type 
+  
+    Rat.Dog
+  
+  but you supplied 1 arguments.
+
+```
+Okay, hmm. TBH I think this code should have type-checked without user intervention, but the way it printed (`cases Mouse x`) is ambiguous, and UCM assumed `Mouse` meant `Rat.Dog.Mouse` instead of `Cat.Dog.Mouse`, which caused parsing to fail.
+
+I'll fix it by making it explicit:
+
+```unison
+countCat : Cat.Dog -> Rat.Dog
+countCat = cases Cat.Dog.Mouse x -> Bird
+
+unique type Rat.Dog = Bird | Mouse
+```
+
+```ucm
+
+  I found and typechecked these definitions in scratch.u. If you
+  do an `add` or `update`, here's how your codebase would
+  change:
+  
+    ⍟ These names already exist. You can `update` them to your
+      new definition:
+    
+      unique type Rat.Dog
+      countCat : Cat.Dog -> Rat.Dog
+
+```
+Ok, all set! Now let's update.
+
+```ucm
+.> update
+
+  Okay, I'm searching the branch for code that needs to be
+  updated...
+
+  That's done. Now I'm making sure everything typechecks...
+
+  countCat : Cat.Dog -> Rat.Dog
+  countCat = cases Mouse x -> Rat.Dog.Bird
+  
+  unique type Rat.Dog = Bird | Mouse
+
+  Typechecking failed. I've updated your scratch file with the
+  definitions that need fixing. Once the file is compiling, try
+  `update` again.
+
+```
+Why is it still printing just `Mouse and failing?