Not only is the test failing, but if you modify line 13 from â(1 to: 2) do: â to â(1 to: 1) do:â in #doTestDebuggerTempAccessWith:with: then Pharo will crash post spur, while pre spur the last assertion will fail. Best regards, Henrik From: Pharo-dev [mailto:pharo-dev-bounces@lists.pharo.org] On Behalf Of Nicolai Hess Sent: Thursday, March 24, 2016 9:53 AM To: Pharo Development List <pharo-dev@lists.pharo.org>; The general-purpose Squeak developers list <squeak-dev@lists.squeakfoundation.org> Subject: [Pharo-dev] modifying copied context vars Hello, we have a failing test (OCClosureCompilerTest>>#testDebuggerTempAccess) (fails since spur, but not related - I think). A simple example to reproduce the behavior: | local1 remote1| remote1:=4. local1 :=3. [:i | |c| c := local1. remote1 := i. i halt. "local1:=25. <-- evaluate during debugging" ] value:1. Transcript show:local1;cr. Transcript show:remote1;cr. (Executing this code and evaluating "local:=25" after the debugger halts for "i halt" will modify the var "remote1" instead of "local1", as this is a vector tempvar , proceeding the execution will crash at accessing the remote1 value). The purpose of the testDebuggerTempAccess test case is, evaluating code that changes the value of a copied temp var *does not* change the value of this var in the outer context. (see comment in the test case: "this is not 25 as the var is a local, non escaping variable that was copied into the block, If the compiler would have known about the write, it would have made the var escaping". ) But the implementation (OCCopyingTempVariable>>#writeFromContext: aContext scope: contextScope value: aValue) explicitly iterates through all outer context(s) and changes the vars as well. 1. Question: Who is right? But the reason why the test actually fails is different. It is because evaluating the code that modifies the var "local1:=25" ends up to a call aContext tempAt: self indexFromIR put: aValue but the index (indexFromIR) can be different for every context (method context / inner block context(s)). 2. Question: should the index be always the same? thanks inadvance Nicolai ps: since spur (resp. compiler changes that were done for new spur images), the index of tempvars can be different. In pre-spur, this testcase modifies an outer context var, but one that isn't checked (the argument "two"), therefore the test succeed. In spur, this testcase modifes a different outer context var "remote1", and the test fails.