Using enums in ternary if statements has unused variable warnings when compiled

[agohof]

When using enums to get values in a ternary if statement, the transpiled code will set the enums as params but it won't use them to get the results. Instead, it inserts the actual values directly in the return statements.

Example

Using the following enums:

enum ThumbButtonSize
    Width = 40
    Height = 37
end enum

enum ClosedCaptionsButtonSize
    Width = 38
    Height = 30
end enum

This ternary operation:

buttonBaseWidth = (nodeId = "closedCaptions") ? ClosedCaptionsButtonSize.Width : ThumbButtonSize.Width

Will be transpiled into the following code:

buttonBaseWidth = (function(__bsCondition, ClosedCaptionsButtonSize, ThumbButtonSize)
            if __bsCondition then
                return 38
            else
                return 40
            end if
        end function)((nodeId = "closedCaptions"), ClosedCaptionsButtonSize, ThumbButtonSize)

When compiled, there will be unused variable warnings because of the ClosedCaptionsButtonSize and ThumbButtonSize params.

[TwitchBronBron]

Yeah, we need to improve the transpiled output to exclude those enums. Good catch.

[TwitchBronBron]

Any chance you'd be interested in trying to fix this? I think util.getExpressionInfo() needs updated to exclude enums, constants, and interfaces.

brighterscript/src/parser/Expression.ts

Line 1381 in aa92cec

let consequentInfo = util.getExpressionInfo(this.consequent!);

brighterscript/src/util.ts

Lines 1189 to 1214 in aa92cec

	public getExpressionInfo(expression: Expression): ExpressionInfo {
	const expressions = [expression];
	const variableExpressions = [] as VariableExpression[];
	const uniqueVarNames = new Set<string>();
	function expressionWalker(expression) {
	if (isExpression(expression)) {
	expressions.push(expression);
	}
	if (isVariableExpression(expression)) {
	variableExpressions.push(expression);
	uniqueVarNames.add(expression.name.text);
	}
	}
	// Collect all expressions. Most of these expressions are fairly small so this should be quick!
	// This should only be called during transpile time and only when we actually need it.
	expression?.walk(expressionWalker, {
	walkMode: WalkMode.visitExpressions
	});
	//handle the expression itself (for situations when expression is a VariableExpression)
	expressionWalker(expression);
	return { expressions: expressions, varExpressions: variableExpressions, uniqueVarNames: [...uniqueVarNames] };
	}