Bug 24525 – auto ref lambda exp not parsed if used as left-most expression in an expression statement

## test case ```d void main() { int a; (auto ref () {return a;}()) = 0; // OK auto ref () {return a;}() = 0; // NG } ``` ## output (many parser errors) ## notes - Only observed for the 3rd rule (https://dlang.org/spec/expression.html#function_literals). - Must be that the parser takes the path of a declaration,

Under https://dlang.org/spec/statement.html#NonEmptyStatementNoCaseNoDefault grammar block it says: > Any ambiguities in the grammar between Statements and Declarations are resolved by the declarations taking precedence. For: > ref () {return a;}() = 0; A declaration `ref () {return a;}` gets parsed, not an ExpressionStatement. So I think this issue is invalid. It is unfortunate that the function literal syntax starting `ref` or `auto ref` was added, when the function/delegate keyword starting forms can already handle those.

> A declaration `ref () {return a;}` gets parsed Sorry, that may be what is happening, but there is no identifier for the declaration, so it should try to parse an ExpressionStatement.

> Any ambiguities in the grammar between Statements and Declarations are resolved by the declarations taking precedence. yes, I remember the spec about decl/stmt ambiguities but here I think there are none. The parser should lookup after `auto`. If next is `(` or if next two are `ref` then `(`, then it should takes the path of expression. > It is unfortunate that the function literal syntax starting `ref` or `auto ref` was added, when the function/delegate keyword starting forms can already handle those. Indeed. But I'll show you the context: ``` void main() { int a,b,c,d,cond; auto ref () { switch (cond) { case 1: return a; case 2: return b; case 3: return c; default: return d; } }() = 0; } ``` Here, given the size of the lambda, you try to avoid the verbose solution (you can put the lambda between parens however, but according to the specs, that should work w/o).

@ntrel created dlang/dmd pull request #16431 "Fix Bugzilla 24525 - ref lambda not parsed at start of ExpressionStat…" fixing this issue: - Fix Bugzilla 24525 - ref lambda not parsed at start of ExpressionStatement https://github.com/dlang/dmd/pull/16431

dlang/dmd pull request #16431 "Fix Bugzilla 24525 - ref lambda not parsed at start of ExpressionStat…" was merged into master: - 3c3be0716da1b6d2cdbe2ca6517a8b1cec6d7ae2 by Nick Treleaven: Fix Bugzilla 24525 - ref lambda not parsed at start of ExpressionStatement https://github.com/dlang/dmd/pull/16431