Copied temps are copied from the defining context into all the contexts.

If we now change the var in the debugger, it calls #tempNamed:put: on the context.

-> make sure to walk up the context to the definition context of the temp and set the value in the copy

fixes #4782

src/OpalCompiler-Core/OCAbstractMethodScope.class.st

@@ -263,6 +263,21 @@ OCAbstractMethodScope >> removeTemp: tempVar [
 	tempVars removeKey: tempVar name
 ]
 
+{ #category : #'temp vars - copying' }
+OCAbstractMethodScope >> setCopyingTempToAllScopesUpToDefTemp: aVar to: aValue from: aContext [
+	| copiedVar |
+	"we need to update all the copies if we change the value of a copied temp"
+
+	self = aVar scope
+		ifTrue: [ ^ self ].
+	copiedVar := self lookupVar: aVar name.
+	aContext tempAt: copiedVar indexFromIR put: aValue.
+	self outerScope
+		setCopyingTempToAllScopesUpToDefTemp: aVar
+		to: aValue
+		from: (self nextOuterScopeContextOf: aContext)
+]
+
 { #category : #'temp vars' }
 OCAbstractMethodScope >> tempVarNames [
 

src/OpalCompiler-Core/OCCopyingTempVariable.class.st

@@ -54,10 +54,10 @@ OCCopyingTempVariable >> writeFromContext: aContext scope: contextScope value: a
 
 	| definitionContext |
 	definitionContext := contextScope lookupDefiningContextForVariable: self startingFrom: aContext.
-	originalVar writeFromContext: aContext scope: contextScope value: aValue.
-
-	self flag: #FIXME.
 	"we need to change all the copies, too"
+	contextScope setCopyingTempToAllScopesUpToDefTemp: originalVar to: aValue from: aContext.
+	"and the original temp"
+	originalVar writeFromContext: aContext scope: contextScope value: aValue.
 
 	^definitionContext 
 		tempAt: self indexFromIR

src/OpalCompiler-Tests/MethodMapExamples.class.st

@@ -55,6 +55,14 @@ MethodMapExamples >> exampleTempNamedPutCopying2 [
 		 a := b .thisContext tempNamed: 'b' put: 2. thisContext outerContext tempNamed: 'b' ] value
 ]
 
+{ #category : #examples }
+MethodMapExamples >> exampleTempNamedPutCopying3 [
+	| b |
+	b := 1.
+	^[[ | a |
+		 a := b .thisContext tempNamed: 'b' put: 2. thisContext outerContext tempNamed: 'b' ] value ] value
+]
+
 { #category : #examples }
 MethodMapExamples >> exampleTempNamedPutTempVector [
 	| b |

src/OpalCompiler-Tests/MethodMapTest.class.st

@@ -127,6 +127,13 @@ MethodMapTest >> testExampleTempNamedPutCopying2 [
 	self assert: (self compileAndRunExample: #exampleTempNamedPutCopying2) equals: 2
 ]
 
+{ #category : #'testing - temp access' }
+MethodMapTest >> testExampleTempNamedPutCopying3 [
+	"modifying a copied temp variable will modify the value in the outer context"
+
+	self assert: (self compileAndRunExample: #exampleTempNamedPutCopying3) equals: 2
+]
+
 { #category : #'testing - temp access' }
 MethodMapTest >> testExampleTempNamedPutTempVector [
 	self assert: (self compileAndRunExample: #exampleTempNamedPutTempVector) equals: 3.