Shadowing bug in inlining affecting foreach

[jeromesimeon]

Describe the bug
Inlining does not handle local variable shadowing properly when within foreach expressions.

To Reproduce

The following zip contains a simple test:
inlinetest.zip

Unzip the file and execute the contract with the following command:

ergorun.js execute model.cto logic.ergo --contract contract.json --request request.json  

For the following expression in the test clause:

    return MyResponse{
			output1: let c = 2; c,
			output2: foreach c in [1,2,3] return c
		}

The result is:

{
    "$class": "org.accordproject.inline.MyResponse",
    "output1": 2,
    "output2": [1, 1, 1],
    "transactionId": "07c93b3c-2750-46aa-a8a7-488cf9ade69c",
    "timestamp": "2019-07-26T00:13:41.028Z"
  }

The local variable c shadows the global constant c properly for the let expression, but not for the foreach expression.

Expected behavior

The expected result should be:

{
    "$class": "org.accordproject.inline.MyResponse",
    "output1": 2,
    "output2": [1, 2, 3],
    "transactionId": "07c93b3c-2750-46aa-a8a7-488cf9ade69c",
    "timestamp": "2019-07-26T00:13:41.028Z"
  }

Desktop (please complete the following information):

• OS: MacOS
• Browser N/A
• Version 0.9

[jeromesimeon]

The most likely reason for the bug is that the generic mapper for expressions used inside the inlining phase, does not record variables from the foreach expression properly in the context:

The corresponding code is at:

ergo/mechanization/Ergo/Lang/ErgoMap.v

Line 102 in 6e755cd

| EForeach loc rs whr fn' =>

Which does not call the ctxt_new_variable_scope.

In contrast, here is the corresponding call for let:

ergo/mechanization/Ergo/Lang/ErgoMap.v

Line 73 in 6e755cd

(ergo_map_expr (ctxt_new_variable_scope ctx n v) ctxt_new_variable_scope fn b)

[jeromesimeon]

Addressed in #640