diff --git a/src/compiler/scala/tools/nsc/backend/icode/analysis/TypeFlowAnalysis.scala b/src/compiler/scala/tools/nsc/backend/icode/analysis/TypeFlowAnalysis.scala
index 962c47f44321..e79193647081 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/analysis/TypeFlowAnalysis.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/analysis/TypeFlowAnalysis.scala
@@ -736,7 +736,13 @@ abstract class TypeFlowAnalysis {
               val succs = point.successors filter relevantBBs
               succs foreach { p =>
                 assert((p.predecessors filter isOnPerimeter).isEmpty)
-                val updated = lattice.lub(List(output, in(p)), p.exceptionHandlerStart)
+                val existing = in(p)
+                // TODO move the following assertion to typeFlowLattice.lub2 for wider applicability (ie MethodTFA in addition to MTFAGrowable).
+                assert(existing == lattice.bottom ||
+                       p.exceptionHandlerStart    ||
+                       (output.stack.length == existing.stack.length),
+                       "Trying to merge non-bottom type-stacks with different stack heights. For a possible cause see SI-6157.")
+                val updated = lattice.lub(List(output, existing), p.exceptionHandlerStart)
                 if(updated != in(p)) {
                   in(p) = updated
                   enqueue(p)
diff --git a/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala b/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
index dd7676a3719d..22f0a9ca7c98 100644
--- a/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
+++ b/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
@@ -981,8 +981,8 @@ abstract class Inliners extends SubComponent {
           return DontInlineHere("too low score (heuristics)")
         }
 
-        if(inc.hasHandlers && (stackLength != 0)) {
-          // TODO pending return DontInlineHere("callee contains exception handlers / finally clause, and is invoked with non-empty operand stack") // SI-6157
+        if(inc.hasHandlers && (stackLength > inc.minimumStack)) {
+          return DontInlineHere("callee contains exception handlers / finally clause, and is invoked with non-empty operand stack") // SI-6157
         }
 
         if(isKnownToInlineSafely) { return InlineableAtThisCaller }
diff --git a/test/files/pos/t6157.flags b/test/files/pos/t6157.flags
new file mode 100644
index 000000000000..0ebca3e7afeb
--- /dev/null
+++ b/test/files/pos/t6157.flags
@@ -0,0 +1 @@
+ -optimize 
diff --git a/test/files/pos/t6157.scala b/test/files/pos/t6157.scala
new file mode 100644
index 000000000000..7463989b14c1
--- /dev/null
+++ b/test/files/pos/t6157.scala
@@ -0,0 +1,25 @@
+//  SI-6157 - Compiler crash on inlined function and -optimize option
+
+object Test {
+  def main(args: Array[String]) {
+    Console.println(
+      ErrorHandler.defaultIfIOException("String")("String")
+    )
+  }
+}
+
+import java.io.IOException
+
+object ErrorHandler {
+
+  @inline
+  def defaultIfIOException[T](default: => T)(closure: => T): T = {
+    try {
+      closure
+    } catch {
+      case e: IOException =>
+        default
+    }
+  }
+}
+
diff --git a/test/files/run/private-inline.scala b/test/files/run/private-inline.scala
index a45300b0267f..a62007779c5e 100644
--- a/test/files/run/private-inline.scala
+++ b/test/files/run/private-inline.scala
@@ -30,7 +30,7 @@ final class A {
 }
 
 object Test {
-  def methodClasses = List("f1a", "f1b", "f2a", "f2b") map ("A$$anonfun$" + _ + "$1")
+  def methodClasses = List("f1a", "f2a") map ("A$$anonfun$" + _ + "$1")
   
   def main(args: Array[String]): Unit = {
     val a = new A