Fix bug with ternary transpile for indexed set

src/bscPlugin/transpile/BrsFilePreTranspileProcessor.ts

@@ -131,7 +131,8 @@ export class BrsFilePreTranspileProcessor {
                 }),
                 endIf: createToken(TokenKind.EndIf, 'end if', ternaryExpression.questionMarkToken.range)
             });
-        } else if (isIndexedSetStatement(parent)) {
+            //if this is an indexedSetStatement, and the ternary expression is NOT an index
+        } else if (isIndexedSetStatement(parent) && parent.index !== ternaryExpression && !parent.additionalIndexes?.includes(ternaryExpression)) {
             ifStatement = createIfStatement({
                 if: createToken(TokenKind.If, 'if', ternaryExpression.questionMarkToken.range),
                 condition: ternaryExpression.test,

src/parser/tests/expression/TernaryExpression.spec.ts

@@ -827,6 +827,27 @@ describe('ternary expressions', () => {
             );
         });
 
+        it('supports ternary in indexedSet key', () => {
+            testTranspile(
+                `
+                    sub main()
+                        m[m.useAltKey ? m.altKey : m.key] = 1
+                    end sub
+                `,
+                `
+                    sub main()
+                        m[(function(__bsCondition, m)
+                                if __bsCondition then
+                                    return m.altKey
+                                else
+                                    return m.key
+                                end if
+                            end function)(m.useAltKey, m)] = 1
+                    end sub
+                `
+            );
+        });
+
         it('supports scope-captured outer, and simple inner', () => {
             testTranspile(
                 `