expressionoperator-precedencerascaldisambiguation

Expression precedence and disambiguation

I'm currently working on making Rust-lang parsable with Rascal. The originally used syntax is made for Bison and so I'm translating it to be usable. The stumbling blocks that I have reached are the expressions. Rust has four types of expressions in its Bison file and those are nonblock_expr, expr, nonparen_expr and expr_nostruct. My existing translations are full of ambiguities but even after reading the Rascal documentation about the topic and the available syntax for Rascal and Java, I'm not sure how to solve this problem. I would like to fix the ambiguities and better understand how this problem could be fixed further.

Here is an example of my translation:

syntax Expression
    = Literal
    > Path_expression
    | "self"
    | Macro_expression
    | Path_expression "{" Structure_expression_fields "}"
    | Expression "." Path_generic_args_with_colons
    //> left Expression "." Literal_integer
    | Expression "[" Expression? "]"
    | Expression "(" (Expressions ","?)? ")"
    | "(" (Expressions ","?)? ")"
    | "[" Vector_expression "]"
    | "continue"
    | "continue" Identifier
    | "return"
    | "return" Expression
    | "break"
    | "break" Identifier
    > left  ( Expression "*" Expression
            | Expression "/" Expression
            | Expression "%" Expression
            )
    > left  ( Expression "+" Expression
            | Expression "-" Expression
            > Expression "\<\<" Expression
            | Expression "\>\>" Expression
            > Expression "&" Expression
            > Expression "^" Expression
            > Expression "|" Expression
            > Expression "\<" Expression
            | Expression "\>" Expression
            | Expression "\<=" Expression
            | Expression "\>=" Expression
            > Expression "==" Expression
            | Expression "!=" Expression
            > Expression "||" Expression
            > Expression "&&" Expression
            )
    > right Expression "\<-" Expression
    > right ( Expression "=" Expression
            | Expression "\<\<=" Expression
            | Expression "\>\>=" Expression
            | Expression "-=" Expression
            | Expression "&=" Expression
            | Expression "|=" Expression
            | Expression "+=" Expression
            | Expression "*=" Expression
            | Expression "/=" Expression
            | Expression "^=" Expression
            | Expression "%=" Expression
            )
    | Expression ".."
    | Expression ".." Expression
    | ".." Expression
    | ".."
    | Expression "as" Type
    | "box" Nonparen_expression
    > "box" "(" Expression? ")" Expression
    | Expression_qualified_path
    | Block_expression
    | Block
    | Nonblock_prefix_expression
    ;

Sources:

Rust Bison file: Github Rust

Oxidize Rascal file: Github Oxidize

Added ambiguity example This is an example of an input file (just the ambiguous part of a file being in the parameters of parse).

fn main() {
    let mut config = Config::parse(&flags.build, flags.config.clone());
}

The output parse tree as seen bellow seems to be confused about the construction of the prefixed expression (&). This ambiguity can't decide between the Nonblock_prefix_expression and Expression "." Path_generic_args_with_colons. I expect it to parse through the Nonblock_prefix_expression. enter image description here

Solution