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Rust: Adjust the inferred type of string literals #19996

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Merged
merged 3 commits into from
Jul 8, 2025
Merged

Rust: Adjust the inferred type of string literals #19996

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73f854f
Rust: Adjust the inferred type of string literals
hvitved Jul 8, 2025
2a207f9
Rust: Update inline expectations
hvitved Jul 8, 2025
22b833f
Rust: Fix bad join
hvitved Jul 8, 2025
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20 changes: 14 additions & 6 deletions rust/ql/lib/codeql/rust/internal/TypeInference.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -1045,14 +1045,15 @@ private Type inferTryExprType(TryExpr te, TypePath path) {
}

pragma[nomagic]
private StructType inferLiteralType(LiteralExpr le) {
private StructType getStrStruct() { result = TStruct(any(Builtins::Str s)) }

pragma[nomagic]
private Type inferLiteralType(LiteralExpr le, TypePath path) {
path.isEmpty() and
exists(Builtins::BuiltinType t | result = TStruct(t) |
le instanceof CharLiteralExpr and
t instanceof Builtins::Char
or
le instanceof StringLiteralExpr and
t instanceof Builtins::Str
or
le =
any(NumberLiteralExpr ne |
t.getName() = ne.getSuffix()
Expand All @@ -1070,6 +1071,14 @@ private StructType inferLiteralType(LiteralExpr le) {
le instanceof BooleanLiteralExpr and
t instanceof Builtins::Bool
)
or
le instanceof StringLiteralExpr and
(
path.isEmpty() and result = TRefType()
or
path = TypePath::singleton(TRefTypeParameter()) and
result = getStrStruct()
)
}

pragma[nomagic]
Expand Down Expand Up @@ -1635,8 +1644,7 @@ private module Cached {
or
result = inferTryExprType(n, path)
or
result = inferLiteralType(n) and
path.isEmpty()
result = inferLiteralType(n, path)
or
result = inferAsyncBlockExprRootType(n) and
path.isEmpty()
Expand Down
10 changes: 5 additions & 5 deletions rust/ql/test/library-tests/type-inference/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1413,7 +1413,7 @@ mod builtins {
let z = x + y; // $ type=z:i32 method=add
let z = x.abs(); // $ method=abs $ type=z:i32
let c = 'c'; // $ type=c:char
let hello = "Hello"; // $ type=hello:str
let hello = "Hello"; // $ type=hello:&T.str
let f = 123.0f64; // $ type=f:f64
let t = true; // $ type=t:bool
let f = false; // $ type=f:bool
Expand Down Expand Up @@ -2086,10 +2086,10 @@ mod loops {
let vals4: [u64; 3] = [1; 3]; // $ type=vals4:[T;...].u64
for u in vals4 {} // $ type=u:u64

let mut strings1 = ["foo", "bar", "baz"]; // $ type=strings1:[T;...].str
for s in &strings1 {} // $ type=s:&T.str
for s in &mut strings1 {} // $ type=s:&T.str
for s in strings1 {} // $ type=s:str
let mut strings1 = ["foo", "bar", "baz"]; // $ type=strings1:[T;...].&T.str
for s in &strings1 {} // $ type=s:&T.&T.str
for s in &mut strings1 {} // $ type=s:&T.&T.str
for s in strings1 {} // $ type=s:&T.str

let strings2 = // $ type=strings2:[T;...].String
[
Expand Down
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