Problems reported:

parser/error_recovery/extension_member_contributor_test_completion:7:5: Expected ';' after this.
  l.a /* the user is typing here */
    ^

parser/error_recovery/extension_member_contributor_test_completion:11:3: Expected ';' after this.
  print(l.b);
  ^^^^^

beginCompilationUnit(extension)
  beginMetadataStar(extension)
  endMetadataStar(0)
  beginExtensionDeclarationPrelude(extension)
    beginTypeVariables(<)
      beginMetadataStar(T)
      endMetadataStar(0)
      handleIdentifier(T, typeVariableDeclaration)
      beginTypeVariable(T)
        handleTypeVariablesDefined(num, 1)
        handleIdentifier(num, typeReference)
        handleNoTypeArguments(>)
        handleType(num, null)
      endTypeVariable(>, 0, extends, null)
    endTypeVariables(<, >)
    beginExtensionDeclaration(extension, E)
      handleIdentifier(List, typeReference)
      beginTypeArguments(<)
        handleIdentifier(T, typeReference)
        handleNoTypeArguments(>)
        handleType(T, null)
      endTypeArguments(1, <, >)
      handleType(List, null)
      handleExtensionShowHide(null, 0, null, 0)
      beginClassOrMixinOrExtensionBody(DeclarationKind.Extension, {)
        beginMetadataStar(bool)
        endMetadataStar(0)
        beginMember()
          beginMethod(DeclarationKind.Extension, null, null, null, null, null, null, a)
            handleIdentifier(bool, typeReference)
            handleNoTypeArguments(a)
            handleType(bool, null)
            handleIdentifier(a, methodDeclaration)
            handleNoTypeVariables(()
            beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
              beginMetadataStar(int)
              endMetadataStar(0)
              beginFormalParameter(int, MemberKind.ExtensionNonStaticMethod, null, null, null)
                handleIdentifier(int, typeReference)
                handleNoTypeArguments(b)
                handleType(int, null)
                handleIdentifier(b, formalParameterDeclaration)
                handleFormalParameterWithoutValue(,)
              endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
              beginMetadataStar(int)
              endMetadataStar(0)
              beginFormalParameter(int, MemberKind.ExtensionNonStaticMethod, null, null, null)
                handleIdentifier(int, typeReference)
                handleNoTypeArguments(c)
                handleType(int, null)
                handleIdentifier(c, formalParameterDeclaration)
                handleFormalParameterWithoutValue())
              endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
            endFormalParameters(2, (, ), MemberKind.ExtensionNonStaticMethod)
            handleNoInitializers()
            handleAsyncModifier(null, null)
            beginBlockFunctionBody({)
            endBlockFunctionBody(0, {, })
          endExtensionMethod(null, bool, (, null, })
        endMember()
        beginMetadataStar(int)
        endMetadataStar(0)
        beginMember()
          beginMethod(DeclarationKind.Extension, null, null, null, null, null, get, b)
            handleIdentifier(int, typeReference)
            handleNoTypeArguments(get)
            handleType(int, null)
            handleIdentifier(b, methodDeclaration)
            handleNoTypeVariables(=>)
            handleNoFormalParameters(=>, MemberKind.ExtensionNonStaticMethod)
            handleNoInitializers()
            handleAsyncModifier(null, null)
            handleLiteralInt(0)
            handleExpressionFunctionBody(=>, ;)
          endExtensionMethod(get, int, =>, null, ;)
        endMember()
        beginMetadataStar(set)
        endMetadataStar(0)
        beginMember()
          beginMethod(DeclarationKind.Extension, null, null, null, null, null, set, c)
            handleNoType(;)
            handleIdentifier(c, methodDeclaration)
            handleNoTypeVariables(()
            beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
              beginMetadataStar(int)
              endMetadataStar(0)
              beginFormalParameter(int, MemberKind.ExtensionNonStaticMethod, null, null, null)
                handleIdentifier(int, typeReference)
                handleNoTypeArguments(d)
                handleType(int, null)
                handleIdentifier(d, formalParameterDeclaration)
                handleFormalParameterWithoutValue())
              endFormalParameter(null, null, null, d, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
            endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
            handleNoInitializers()
            handleAsyncModifier(null, null)
            beginBlockFunctionBody({)
            endBlockFunctionBody(0, {, })
          endExtensionMethod(set, set, (, null, })
        endMember()
      endClassOrMixinOrExtensionBody(DeclarationKind.Extension, 3, {, })
    endExtensionDeclaration(extension, null, on, null, null, })
  endTopLevelDeclaration(void)
  beginMetadataStar(void)
  endMetadataStar(0)
  beginTopLevelMember(void)
    beginTopLevelMethod(}, null, null)
      handleVoidKeyword(void)
      handleIdentifier(f, topLevelFunctionDeclaration)
      handleNoTypeVariables(()
      beginFormalParameters((, MemberKind.TopLevelMethod)
        beginMetadataStar(List)
        endMetadataStar(0)
        beginFormalParameter(List, MemberKind.TopLevelMethod, null, null, null)
          handleIdentifier(List, typeReference)
          beginTypeArguments(<)
            handleIdentifier(int, typeReference)
            handleNoTypeArguments(>)
            handleType(int, null)
          endTypeArguments(1, <, >)
          handleType(List, null)
          handleIdentifier(l, formalParameterDeclaration)
          handleFormalParameterWithoutValue())
        endFormalParameter(null, null, null, l, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
      endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
      handleAsyncModifier(null, null)
      beginBlockFunctionBody({)
        handleIdentifier(l, expression)
        handleNoTypeArguments(.)
        handleNoArguments(.)
        handleSend(l, .)
        handleIdentifier(a, expressionContinuation)
        handleNoTypeArguments(})
        handleNoArguments(})
        handleSend(a, })
        handleEndingBinaryExpression(.)
        handleRecoverableError(Message[ExpectedAfterButGot, Expected ';' after this., null, {string: ;}], a, a)
        handleExpressionStatement(;)
      endBlockFunctionBody(1, {, })
    endTopLevelMethod(void, null, })
  endTopLevelDeclaration(void)
  beginMetadataStar(void)
  endMetadataStar(0)
  beginTopLevelMember(void)
    beginTopLevelMethod(}, null, null)
      handleVoidKeyword(void)
      handleIdentifier(g, topLevelFunctionDeclaration)
      handleNoTypeVariables(()
      beginFormalParameters((, MemberKind.TopLevelMethod)
        beginMetadataStar(List)
        endMetadataStar(0)
        beginFormalParameter(List, MemberKind.TopLevelMethod, null, null, null)
          handleIdentifier(List, typeReference)
          beginTypeArguments(<)
            handleIdentifier(int, typeReference)
            handleNoTypeArguments(>)
            handleType(int, null)
          endTypeArguments(1, <, >)
          handleType(List, null)
          handleIdentifier(l, formalParameterDeclaration)
          handleFormalParameterWithoutValue())
        endFormalParameter(null, null, null, l, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
      endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
      handleAsyncModifier(null, null)
      beginBlockFunctionBody({)
        beginMetadataStar(l)
        endMetadataStar(0)
        handleIdentifier(l, prefixedTypeReference)
        handleIdentifier(a, typeReferenceContinuation)
        handleQualified(.)
        handleNoTypeArguments(print)
        handleType(l, null)
        beginVariablesDeclaration(print, null, null)
          handleIdentifier(print, localVariableDeclaration)
          beginInitializedIdentifier(print)
            handleNoVariableInitializer(print)
          endInitializedIdentifier(print)
          handleRecoverableError(Message[ExpectedAfterButGot, Expected ';' after this., null, {string: ;}], print, print)
        endVariablesDeclaration(1, ;)
        handleIdentifier(l, expression)
        handleNoTypeArguments(.)
        handleNoArguments(.)
        handleSend(l, .)
        handleIdentifier(b, expressionContinuation)
        handleNoTypeArguments())
        handleNoArguments())
        handleSend(b, ))
        handleEndingBinaryExpression(.)
        handleParenthesizedExpression(()
        handleExpressionStatement(;)
      endBlockFunctionBody(2, {, })
    endTopLevelMethod(void, null, })
  endTopLevelDeclaration()
endCompilationUnit(3, )