Fixed bugs in the type checker for switch: test for exiting in a way …

…that includes revert, and when merging with initial branches that exit, pass the appropriate flag to the merging code.
mcoblenz · May 5, 2020 · 0bff4e6 · 0bff4e6
1 parent 1cb8291
commit 0bff4e6
Showing 1 changed file with 7 additions and 2 deletions.
diff --git a/src/main/scala/edu/cmu/cs/obsidian/typecheck/Checker.scala b/src/main/scala/edu/cmu/cs/obsidian/typecheck/Checker.scala
@@ -2180,13 +2180,18 @@ class Checker(globalTable: SymbolTable, verbose: Boolean = false) {
                         // If a given switch case is guaranteed to return, then if it DID run, then the code BELOW this will NEVER run, so
                         // we need not merge the case's output context in.
                         val (firstCaseOutputContext, newCase) = checkSwitchCase(switchCase)
+                        val firstCaseExits = hasReturnStatementDontLog(switchCase.body) || firstCaseOutputContext.isThrown
 
-                        val initialContextToMerge = if (hasReturnStatementDontLog(switchCase.body)) contextPrime else firstCaseOutputContext
+
+                        var foundNonExitingCaseYet = !firstCaseExits
+                        val initialContextToMerge = if (firstCaseExits) contextPrime else firstCaseOutputContext
                         val restCases = cases.tail
                         restCases.foldLeft((initialContextToMerge, Seq(newCase)))((prev: (Context, Seq[SwitchCase]), sc: SwitchCase) => {
                             val (newContext, newCase) = checkSwitchCase(sc)
                             val caseExits = hasReturnStatementDontLog(sc.body) || newContext.isThrown
-                            (mergeContext(s, prev._1, newContext, false, caseExits), newCase +: prev._2)
+                            val res = (mergeContext(s, prev._1, newContext, !foundNonExitingCaseYet, caseExits), newCase +: prev._2)
+                            foundNonExitingCaseYet = foundNonExitingCaseYet || caseExits
+                            res
                         })
                 }