Analyze a pattern guard after the pattern binds its variables

lib/typeprof/core/ast/pattern.rb

@@ -153,8 +153,9 @@ def initialize(raw_node, lenv)
       def subnodes = { cond:, body: }
 
       def install_pattern0(genv, subject)
-        @cond.install(genv)
+        # The guard is evaluated after the pattern binds its variables
         @body.install_pattern(genv, subject)
+        @cond.install(genv)
         subject
       end
     end

scenario/patterns/guard_binding.rb

@@ -0,0 +1,30 @@
+## update: test.rb
+def cond?(x)
+  x
+end
+
+def check_if(v)
+  case v
+  in [x] if cond?(x).even?
+    x
+  end
+end
+
+def check_unless(v)
+  case v
+  in [_, y] unless cond?(y).even?
+    y
+  end
+end
+
+check_if([1])
+check_unless([:a, 1])
+
+## diagnostics
+
+## assert
+class Object
+  def cond?: (Integer) -> Integer
+  def check_if: ([Integer]) -> Integer
+  def check_unless: ([:a, Integer]) -> Integer
+end