Eliot Miranda uploaded a new version of Compiler to project The Trunk:
http://source.squeak.org/trunk/Compiler-eem.289.mcz

==================== Summary ====================

Name: Compiler-eem.289
Author: eem
Time: 6 October 2014, 11:58:50.62 am
UUID: 7d67c48c-4a2f-4445-83e8-1f8f931801e3
Ancestors: Compiler-eem.288

Fix doits in the codePane of a debugger opened from
another debugger.  e.g. before this fix

1. debug 3+4.
2. in code pane of debugger #1 debug 4+5
3. in code pane of debugger #2 debug 5+6, boom.

The bug was that when the encoder creates temp names for temp vars in the debugged context, which
it does by creating messages to DoItIn:'s argument
'ThisContext', if this is a level 3 debug, then the
original expression would have a temp var called
'ThisContext' already and that would overwrite the
'ThisContext' argument for this level with a
message send, and boom.

The fix is merely to filter-out these temps and
hence never overwrite DoItIn:'s 'ThisContext'
argument in the scope table.

=============== Diff against Compiler-eem.288 ===============

Item was changed:
  ----- Method: Encoder>>init:notifying: (in category 'initialize-release') -----
  init: aCue notifying: anObject
  	"The use of the variable requestor is a bit confusing here. This is
  	*not* the original requestor, which is available through the cue.
  	It's the Parser instance that is using the encoder."
  
  	self setCue: aCue.
  	requestor := anObject.
  	nTemps := 0.
  	supered := false.
  	self initScopeAndLiteralTables.
  	cue getClass variablesAndOffsetsDo:
  		[:variable "<String|CFieldDefinition>" :offset "<Integer|nil>" |
  		offset isNil
  			ifTrue: [scopeTable at: variable name put: (FieldNode new fieldDefinition: variable)]
  			ifFalse: [scopeTable
  						at: variable
  						put: (offset >= 0
  								ifTrue: [InstanceVariableNode new
  											name: variable index: offset]
  								ifFalse: [MaybeContextInstanceVariableNode new
  											name: variable index: offset negated])]].
  	cue context ~~ nil ifTrue:
  		[| homeNode |
  		 homeNode := self bindTemp: self doItInContextName.
  		 "0th temp = aContext passed as arg"
  		 cue context tempNames withIndexDo:
  			[:variable :index|
+ 			variable ~= self doItInContextName ifTrue:
+ 				[scopeTable
+ 					at: variable
+ 					put: (MessageAsTempNode new
+ 							receiver: homeNode
+ 							selector: #namedTempAt:
+ 							arguments: (Array with: (self encodeLiteral: index))
+ 							precedence: 3
+ 							from: self)]]].
- 			scopeTable
- 				at: variable
- 				put: (MessageAsTempNode new
- 						receiver: homeNode
- 						selector: #namedTempAt:
- 						arguments: (Array with: (self encodeLiteral: index))
- 						precedence: 3
- 						from: self)]].
  	sourceRanges := Dictionary new: 32.
  	globalSourceRanges := OrderedCollection new: 32
  !