Ruby: CFG: fix completion of AsPattern variable

Author: aibaars

ruby/ql/lib/codeql/ruby/controlflow/internal/ControlFlowGraphImpl.qll

@@ -711,7 +711,8 @@ module Trees {
       last(this.getPattern(), last, c) and
       c.(MatchingCompletion).getValue() = false
       or
-      last(this.getVariableAccess(), last, c)
+      last(this.getVariableAccess(), last, any(SimpleCompletion x)) and
+      c.(MatchingCompletion).getValue() = true
     }
 
     final override predicate succ(AstNode pred, AstNode succ, Completion c) {

ruby/ql/test/library-tests/controlflow/graph/Cfg.expected

@@ -1190,8 +1190,14 @@ case.rb:
 #-----| match -> x
 
 #   82| x
+#-----| match -> 1
+
+#   82| then ...
 #-----|  -> case ...
 
+#   82| 1
+#-----|  -> then ...
+
 #   83| in ... then ...
 #-----|  -> ... | ...
 

ruby/ql/test/library-tests/controlflow/graph/case.rb

@@ -79,7 +79,7 @@ def case_match_various value
     in 5 .. 10
     in .. 10
     in 5 ..
-    in 5 => x
+    in 5 => x then 1
     in 5 | ^foo | "string"
     in ::Foo::Bar
     in -> x { x == 10 }