Let c1[c2] be a compile time constant expression.

[lrhn]

If c1 is a compile-time constant List, Map or String, and c2 is a compile-time constant too, we could allow c1[c2] as a compile-time constant expression.

It will throw if c1 is a List or String and c2 is not an integer or it is < 0 or >= c1.length. The result is either the element at index c2, if c1 is a List, or the substring of length 1 at index c2 when c1 is a String.

If c1 is a Map, any key is allowed, and c1[c2] evaluates to null if c2 isn't a key in the map - since the keys of a constant map must not override operator==, the lookup is a safe constant operation.

[DartBot]

This comment was originally written by trpasl...@gmail.com

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possibe duplicate of https://code.google.com/p/dart/issues/detail?id=18389

[lrhn]

It is a duplicate, only with only the addition of String indexing. Merging with older issue.

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Added Duplicate label.
Marked as being merged into #18389.