Check on enum variant type matching in patterns

[eytan-starkware]

When building a semantic model a check is expected that pattern is legal.
When we match an option, we expect a case Some to be illegal, as it ignores the parameter. The expected pattern would be Some(_).
This PR adds that check.

[reviewable-StarkWare]

This change is 

[TomerStarkware]

Reviewed 1 of 4 files at r1, all commit messages.
Reviewable status: 1 of 4 files reviewed, 3 unresolved discussions (waiting on @orizi)

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crates/cairo-lang-semantic/src/expr/test_data/match line 260 at r1 (raw file):

//! > ==========================================================================

//! > Test match on variant without args.

add a test where we use A::One and match on the pattern One

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crates/cairo-lang-semantic/src/expr/compute.rs line 2630 at r1 (raw file):

    let (concrete_enum, n_snapshots) =
        extract_concrete_enum_from_pattern_and_validate(ctx, pattern, ty, generic_variant.enum_id)?;
    let db = ctx.db;

The local db variable is unnecessary

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crates/cairo-lang-semantic/src/expr/compute.rs line 2638 at r1 (raw file):

        .map_err(|_| ctx.diagnostics.report(pattern.stable_ptr(db), UnknownEnum))?;

    let needs_args = concrete_variant.ty != unit_ty(db);

using concre_variant.ty means we Option<()>::Some does not need args,
is this intended? add tests

[orizi]

Reviewed all commit messages.
Reviewable status: 1 of 4 files reviewed, 3 unresolved discussions (waiting on @eytan-starkware and @TomerStarkware)

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crates/cairo-lang-semantic/src/expr/compute.rs line 2630 at r1 (raw file):

Previously, TomerStarkware wrote…

The local db variable is unnecessary

it is fine IMO - as it is used a lot of times.

[eytan-starkware]

Reviewable status: 1 of 4 files reviewed, 3 unresolved discussions (waiting on @orizi and @TomerStarkware)

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crates/cairo-lang-semantic/src/expr/compute.rs line 2630 at r1 (raw file):

Previously, orizi wrote…

it is fine IMO - as it is used a lot of times.

Actually added another use now

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crates/cairo-lang-semantic/src/expr/compute.rs line 2638 at r1 (raw file):

Previously, TomerStarkware wrote…

using concre_variant.ty means we Option<()>::Some does not need args,
is this intended? add tests

Changed it to use generic_variant to have consistent error reporting as discussed

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crates/cairo-lang-semantic/src/expr/test_data/match line 260 at r1 (raw file):

Previously, TomerStarkware wrote…

add a test where we use A::One and match on the pattern One

Done

[orizi]

Reviewed 2 of 3 files at r2.
Reviewable status: 3 of 4 files reviewed, 4 unresolved discussions (waiting on @TomerStarkware)

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crates/cairo-lang-semantic/src/diagnostic.rs line 1014 at r2 (raw file):

                "Type constraints syntax is not enabled in the current crate.".into()
            }
            SemanticDiagnosticKind::PatternMissingArgs(variant_id) => {

add that this is a warning instead of an error - to not fully break existing libs.

[TomerStarkware]

Reviewed 1 of 3 files at r2, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @eytan-starkware)

[eytan-starkware]

Reviewable status: 0 of 6 files reviewed, 1 unresolved discussion (waiting on @orizi and @TomerStarkware)

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crates/cairo-lang-semantic/src/diagnostic.rs line 1014 at r2 (raw file):

Previously, orizi wrote…

add that this is a warning instead of an error - to not fully break existing libs.

Done.

[orizi]

Reviewed all commit messages.
Reviewable status: 0 of 6 files reviewed, 2 unresolved discussions (waiting on @TomerStarkware)

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crates/cairo-lang-lowering/src/test_data/match line 1741 at r3 (raw file):

//! > semantic_diagnostics
warning: Pattern missing subpattern for the parameter of variant `core::option::Option::Some`. Consider using `core::option::Option::Some(_)`

extract Some from the usage to shorten and make clearer.

Suggestion:

warning: Pattern missing subpattern for the payload of variant. Consider using `Some(_)`

[orizi]

Reviewed 1 of 6 files at r3.
Reviewable status: 1 of 6 files reviewed, 1 unresolved discussion (waiting on @eytan-starkware and @TomerStarkware)

[eytan-starkware]

Reviewable status: 0 of 6 files reviewed, 1 unresolved discussion (waiting on @orizi and @TomerStarkware)

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crates/cairo-lang-lowering/src/test_data/match line 1741 at r3 (raw file):

Previously, orizi wrote…

extract Some from the usage to shorten and make clearer.

Done.

[orizi]

Reviewed 5 of 6 files at r4, all commit messages.
Reviewable status: 5 of 6 files reviewed, 2 unresolved discussions (waiting on @TomerStarkware)

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crates/cairo-lang-semantic/src/expr/compute.rs line 2632 at r4 (raw file):

    let db = ctx.db;

    // TODO(lior): Should we report a diagnostic here?

?

Code quote:

    // TODO(lior): Should we report a diagnostic here?

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crates/cairo-lang-semantic/src/expr/compute.rs line 2647 at r4 (raw file):

            ast::Pattern::Enum(pattern) => pattern.path(db),
            ast::Pattern::Path(p) => p.clone(),
            _ => unreachable!(),

Suggestion:

            _ => unreachable!("string explaining why"),

[eytan-starkware]

Reviewable status: 5 of 6 files reviewed, 2 unresolved discussions (waiting on @orizi and @TomerStarkware)

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crates/cairo-lang-semantic/src/expr/compute.rs line 2632 at r4 (raw file):

Previously, orizi wrote…

?

Done.

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crates/cairo-lang-semantic/src/expr/compute.rs line 2647 at r4 (raw file):

            ast::Pattern::Enum(pattern) => pattern.path(db),
            ast::Pattern::Path(p) => p.clone(),
            _ => unreachable!(),

Done.

[orizi]

Reviewed 1 of 1 files at r5, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @eytan-starkware)