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hvitved merged 2 commits into from
Jun 13, 2025
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Rust: Type inference for macro expressions #19751

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Rust: Add macro expr type inference test
hvitved Jun 13, 2025
2f698d1
Rust: Type inference for macro expressions
hvitved Jun 13, 2025
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2 changes: 2 additions & 0 deletions rust/ql/lib/codeql/rust/internal/TypeInference.qll
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Expand Up @@ -265,6 +265,8 @@ private predicate typeEquality(AstNode n1, TypePath prefix1, AstNode n2, TypePat
n1 = be.getLhs() and
n2 = be.getRhs()
)
or
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Copilot AI Jun 13, 2025

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[nitpick] Consider adding a brief comment above this clause explaining why macro expressions require special handling here, improving future maintainability.

Suggested change
or
or
// Macro expressions require special handling because they can expand into multiple
// expressions or statements, which affects type inference.

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n1 = n2.(MacroExpr).getMacroCall().getMacroCallExpansion()
)
or
n1 = n2.(RefExpr).getExpr() and
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7 changes: 7 additions & 0 deletions rust/ql/test/library-tests/type-inference/main.rs
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Expand Up @@ -1810,6 +1810,12 @@ mod indexers {
}
}

mod macros {
pub fn f() {
let x = format!("Hello, {}", "World!"); // $ MISSING: type=x:String -- needs https://github.com/github/codeql/pull/19658
}
}

fn main() {
field_access::f();
method_impl::f();
Expand All @@ -1832,4 +1838,5 @@ fn main() {
async_::f();
impl_trait::f();
indexers::f();
macros::f();
}
18 changes: 13 additions & 5 deletions rust/ql/test/library-tests/type-inference/type-inference.expected
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Expand Up @@ -1021,8 +1021,12 @@ inferType
| main.rs:912:19:912:22 | self | Snd | main.rs:910:15:910:17 | Snd |
| main.rs:913:43:913:82 | MacroExpr | | main.rs:910:15:910:17 | Snd |
| main.rs:913:50:913:81 | "PairNone has no second elemen... | | {EXTERNAL LOCATION} | str |
| main.rs:913:50:913:81 | MacroExpr | | main.rs:910:15:910:17 | Snd |
| main.rs:913:50:913:81 | { ... } | | main.rs:910:15:910:17 | Snd |
| main.rs:914:43:914:81 | MacroExpr | | main.rs:910:15:910:17 | Snd |
| main.rs:914:50:914:80 | "PairFst has no second element... | | {EXTERNAL LOCATION} | str |
| main.rs:914:50:914:80 | MacroExpr | | main.rs:910:15:910:17 | Snd |
| main.rs:914:50:914:80 | { ... } | | main.rs:910:15:910:17 | Snd |
| main.rs:915:37:915:39 | snd | | main.rs:910:15:910:17 | Snd |
| main.rs:915:45:915:47 | snd | | main.rs:910:15:910:17 | Snd |
| main.rs:916:41:916:43 | snd | | main.rs:910:15:910:17 | Snd |
Expand Down Expand Up @@ -2642,9 +2646,13 @@ inferType
| main.rs:1809:24:1809:25 | xs | | file://:0:0:0:0 | [] |
| main.rs:1809:24:1809:25 | xs | [T;...] | main.rs:1764:5:1765:13 | S |
| main.rs:1809:24:1809:25 | xs | [T] | main.rs:1764:5:1765:13 | S |
| main.rs:1815:5:1815:20 | ...::f(...) | | main.rs:67:5:67:21 | Foo |
| main.rs:1816:5:1816:60 | ...::g(...) | | main.rs:67:5:67:21 | Foo |
| main.rs:1816:20:1816:38 | ...::Foo {...} | | main.rs:67:5:67:21 | Foo |
| main.rs:1816:41:1816:59 | ...::Foo {...} | | main.rs:67:5:67:21 | Foo |
| main.rs:1832:5:1832:15 | ...::f(...) | | {EXTERNAL LOCATION} | trait Future |
| main.rs:1815:25:1815:35 | "Hello, {}" | | {EXTERNAL LOCATION} | str |
| main.rs:1815:25:1815:45 | ...::format(...) | | {EXTERNAL LOCATION} | String |
| main.rs:1815:25:1815:45 | { ... } | | {EXTERNAL LOCATION} | String |
| main.rs:1815:38:1815:45 | "World!" | | {EXTERNAL LOCATION} | str |
| main.rs:1821:5:1821:20 | ...::f(...) | | main.rs:67:5:67:21 | Foo |
| main.rs:1822:5:1822:60 | ...::g(...) | | main.rs:67:5:67:21 | Foo |
| main.rs:1822:20:1822:38 | ...::Foo {...} | | main.rs:67:5:67:21 | Foo |
| main.rs:1822:41:1822:59 | ...::Foo {...} | | main.rs:67:5:67:21 | Foo |
| main.rs:1838:5:1838:15 | ...::f(...) | | {EXTERNAL LOCATION} | trait Future |
testFailures