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Rust: Make await call async blocks as lambdas in dataflow #22637

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d099129
Rust: Add async block lambda tests
paldepind Sep 21, 2026
4a60130
Rust: Make `await` call `async` blocks as lambdas in dataflow
paldepind Sep 21, 2026
aa9ce8e
Rust: Accept changes in test results
paldepind Sep 21, 2026
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17 changes: 13 additions & 4 deletions rust/ql/lib/codeql/rust/dataflow/internal/DataFlowImpl.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,9 @@ final class DataFlowCall extends TDataFlowCall {
/** Gets the underlying call, if any. */
Call asCall() { this = TCall(result) }

/** Gets the underlying await expression, if any. */
AwaitExpr asAwaitExpr() { this = TAwaitExpr(result) }

predicate isImplicitDerefCall(Expr e, DerefChain derefChain, int i, Function target) {
this = TImplicitDerefCall(e, derefChain, i, target)
}
Expand All @@ -73,15 +76,16 @@ final class DataFlowCall extends TDataFlowCall {
}

DataFlowCallable getEnclosingCallable() {
result.asCfgScope() = this.asCall().getEnclosingCfgScope()
result.asCfgScope() =
[this.asCall().getEnclosingCfgScope(), this.asAwaitExpr().getEnclosingCfgScope()]
or
result.asCfgScope() = any(Expr e | this.isImplicitDerefCall(e, _, _, _)).getEnclosingCfgScope()
or
this.isSummaryCall(result.asSummarizedCallable(), _)
}

string toString() {
result = this.asCall().toString()
result = [this.asCall().toString(), this.asAwaitExpr().toString()]
or
exists(Expr e, DerefChain derefChain, int i |
this.isImplicitDerefCall(e, derefChain, i, _) and
Expand All @@ -97,7 +101,7 @@ final class DataFlowCall extends TDataFlowCall {
}

Location getLocation() {
result = this.asCall().getLocation()
result = [this.asCall().getLocation(), this.asAwaitExpr().getLocation()]
or
result = any(Expr e | this.isImplicitDerefCall(e, _, _, _)).getLocation()
}
Expand Down Expand Up @@ -1004,7 +1008,11 @@ module RustDataFlowGen<RustDataFlowInputSig Input> implements InputSig<Location>
*/
predicate lambdaCall(DataFlowCall call, LambdaCallKind kind, Node receiver) {
(
receiver.asExpr() = call.asCall().(CallExprImpl::DynamicCallExpr).getFunction()
receiver.asExpr() =
[
call.asCall().(CallExprImpl::DynamicCallExpr).getFunction(),
call.asAwaitExpr().getExpr()
]
or
call.isSummaryCall(_, receiver.(FlowSummaryNode).getSummaryNode())
) and
Expand Down Expand Up @@ -1176,6 +1184,7 @@ private module Cached {
Stages::DataFlowStage::ref() and
call.hasEnclosingCfgScope()
} or
TAwaitExpr(AwaitExpr await) { await.hasEnclosingCfgScope() } or
TImplicitDerefCall(Expr e, DerefChain derefChain, int i, Function target) {
TypeInference::implicitDerefChainBorrow(e, derefChain, _) and
target = derefChain.getElement(i).getDerefFunction() and
Expand Down
19 changes: 19 additions & 0 deletions rust/ql/lib/codeql/rust/dataflow/internal/Node.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -435,6 +435,20 @@ final class ClosureArgumentNode extends ArgumentNode, ExprNode {
}
}

/**
* A data flow node that represents the run-time representation of an async
* block passed into its body when awaited.
*/
final class AsyncBlockArgumentNode extends ArgumentNode, ExprNode {
private AwaitExpr await;

AsyncBlockArgumentNode() { this.asExpr() = await.getExpr() }

override predicate isArgumentOf(DataFlowCall call, RustDataFlow::ArgumentPosition pos) {
call.asAwaitExpr() = await and pos.isClosureSelf()
}
}

/** An SSA node. */
class SsaNode extends Node, TSsaNode {
SsaImpl::DataFlowIntegration::SsaNode node;
Expand Down Expand Up @@ -485,12 +499,17 @@ final private class ExprOutNode extends ExprNode, OutNode {
not call instanceof DerefExpr and // Handled by `DerefOutNode`
not call instanceof IndexExpr // Handled by `IndexOutNode`
)
or
this.asExpr() instanceof AwaitExpr
}

/** Gets the underlying call node that includes this out node. */
override DataFlowCall getCall(ReturnKind kind) {
result.asCall() = n and
kind = TNormalReturnKind()
or
result.asAwaitExpr() = n and
kind = TNormalReturnKind()
}
}

Expand Down
5 changes: 5 additions & 0 deletions rust/ql/test/library-tests/dataflow/global/inline-flow.expected
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Original file line number Diff line number Diff line change
Expand Up @@ -196,7 +196,9 @@ edges
| main.rs:342:9:342:9 | a | main.rs:343:10:343:10 | a | provenance | |
| main.rs:342:13:342:26 | async_source(...) | main.rs:342:9:342:9 | a | provenance | |
| main.rs:346:13:346:13 | c | main.rs:347:14:347:14 | c | provenance | |
| main.rs:346:13:346:13 | c | main.rs:348:9:348:9 | c | provenance | |
| main.rs:346:17:346:25 | source(...) | main.rs:346:13:346:13 | c | provenance | |
| main.rs:348:9:348:9 | c | main.rs:350:10:350:16 | await b | provenance | |
| main.rs:354:9:354:9 | a | main.rs:355:10:355:10 | a | provenance | |
| main.rs:354:13:354:55 | ...::block_on(...) | main.rs:354:9:354:9 | a | provenance | |
| main.rs:354:41:354:54 | async_source(...) | main.rs:354:13:354:55 | ...::block_on(...) | provenance | MaD:3 |
Expand Down Expand Up @@ -443,6 +445,8 @@ nodes
| main.rs:346:13:346:13 | c | semmle.label | c |
| main.rs:346:17:346:25 | source(...) | semmle.label | source(...) |
| main.rs:347:14:347:14 | c | semmle.label | c |
| main.rs:348:9:348:9 | c | semmle.label | c |
| main.rs:350:10:350:16 | await b | semmle.label | await b |
| main.rs:354:9:354:9 | a | semmle.label | a |
| main.rs:354:13:354:55 | ...::block_on(...) | semmle.label | ...::block_on(...) |
| main.rs:354:41:354:54 | async_source(...) | semmle.label | async_source(...) |
Expand Down Expand Up @@ -539,6 +543,7 @@ testFailures
| main.rs:337:10:337:10 | a | main.rs:336:13:336:21 | source(...) | main.rs:337:10:337:10 | a | $@ | main.rs:336:13:336:21 | source(...) | source(...) |
| main.rs:343:10:343:10 | a | main.rs:336:13:336:21 | source(...) | main.rs:343:10:343:10 | a | $@ | main.rs:336:13:336:21 | source(...) | source(...) |
| main.rs:347:14:347:14 | c | main.rs:346:17:346:25 | source(...) | main.rs:347:14:347:14 | c | $@ | main.rs:346:17:346:25 | source(...) | source(...) |
| main.rs:350:10:350:16 | await b | main.rs:346:17:346:25 | source(...) | main.rs:350:10:350:16 | await b | $@ | main.rs:346:17:346:25 | source(...) | source(...) |
| main.rs:355:10:355:10 | a | main.rs:336:13:336:21 | source(...) | main.rs:355:10:355:10 | a | $@ | main.rs:336:13:336:21 | source(...) | source(...) |
| main.rs:404:14:404:15 | n1 | main.rs:379:13:379:21 | source(...) | main.rs:404:14:404:15 | n1 | $@ | main.rs:379:13:379:21 | source(...) | source(...) |
| main.rs:408:14:408:15 | n2 | main.rs:379:13:379:21 | source(...) | main.rs:408:14:408:15 | n2 | $@ | main.rs:379:13:379:21 | source(...) | source(...) |
Expand Down
2 changes: 1 addition & 1 deletion rust/ql/test/library-tests/dataflow/global/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -347,7 +347,7 @@ async fn test_async_await_async_part() {
sink(c); // $ hasValueFlow=2
c
};
sink(b.await); // $ MISSING: hasValueFlow=2
sink(b.await); // $ hasValueFlow=2
}

fn test_async_await() {
Expand Down
144 changes: 144 additions & 0 deletions rust/ql/test/library-tests/dataflow/lambdas/Cargo.lock
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25 changes: 25 additions & 0 deletions rust/ql/test/library-tests/dataflow/lambdas/inline-flow.expected
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,14 @@ edges
| main.rs:111:26:111:36 | \|...\| ... : ... => .. [captured a] | main.rs:111:35:111:35 | a | provenance | heuristic-callback |
| main.rs:112:26:112:36 | \|...\| ... : ... => .. [captured a] | main.rs:112:35:112:35 | a | provenance | heuristic-callback |
| main.rs:113:26:113:36 | \|...\| ... : ... => .. [captured a] | main.rs:113:35:113:35 | a | provenance | heuristic-callback |
| main.rs:120:30:120:40 | source(...) | main.rs:121:14:121:25 | await future | provenance | |
| main.rs:125:20:125:30 | source(...) | main.rs:126:9:128:9 | { ... } : ... => .. [captured data] | provenance | |
| main.rs:126:9:128:9 | { ... } : ... => .. [captured data] | main.rs:127:18:127:21 | data | provenance | |
| main.rs:133:20:133:30 | source(...) | main.rs:135:14:135:19 | future [captured data] | provenance | |
| main.rs:135:14:135:19 | future [captured data] | main.rs:134:30:134:33 | data | provenance | |
| main.rs:135:14:135:19 | future [captured data] | main.rs:135:14:135:25 | await future | provenance | |
| main.rs:141:9:143:9 | [post] { ... } : ... => .. [captured captured] | main.rs:145:14:145:21 | captured | provenance | |
| main.rs:142:24:142:34 | source(...) | main.rs:141:9:143:9 | [post] { ... } : ... => .. [captured captured] | provenance | |
nodes
| main.rs:10:20:10:52 | if cond {...} else {...} | semmle.label | if cond {...} else {...} |
| main.rs:10:30:10:39 | source(...) | semmle.label | source(...) |
Expand Down Expand Up @@ -138,9 +146,22 @@ nodes
| main.rs:112:35:112:35 | a | semmle.label | a |
| main.rs:113:26:113:36 | \|...\| ... : ... => .. [captured a] | semmle.label | \|...\| ... : ... => .. [captured a] |
| main.rs:113:35:113:35 | a | semmle.label | a |
| main.rs:120:30:120:40 | source(...) | semmle.label | source(...) |
| main.rs:121:14:121:25 | await future | semmle.label | await future |
| main.rs:125:20:125:30 | source(...) | semmle.label | source(...) |
| main.rs:126:9:128:9 | { ... } : ... => .. [captured data] | semmle.label | { ... } : ... => .. [captured data] |
| main.rs:127:18:127:21 | data | semmle.label | data |
| main.rs:133:20:133:30 | source(...) | semmle.label | source(...) |
| main.rs:134:30:134:33 | data | semmle.label | data |
| main.rs:135:14:135:19 | future [captured data] | semmle.label | future [captured data] |
| main.rs:135:14:135:25 | await future | semmle.label | await future |
| main.rs:141:9:143:9 | [post] { ... } : ... => .. [captured captured] | semmle.label | [post] { ... } : ... => .. [captured captured] |
| main.rs:142:24:142:34 | source(...) | semmle.label | source(...) |
| main.rs:145:14:145:21 | captured | semmle.label | captured |
subpaths
| main.rs:29:21:29:21 | a | main.rs:27:20:27:23 | ... | main.rs:27:26:27:52 | if cond {...} else {...} | main.rs:29:13:29:22 | f(...) |
| main.rs:77:21:77:21 | a | main.rs:66:24:66:32 | ...: i64 | main.rs:66:42:72:1 | { ... } | main.rs:77:13:77:22 | f(...) |
| main.rs:135:14:135:19 | future [captured data] | main.rs:134:30:134:33 | data | main.rs:134:30:134:33 | data | main.rs:135:14:135:25 | await future |
testFailures
#select
| main.rs:11:10:11:16 | f(...) | main.rs:10:30:10:39 | source(...) | main.rs:11:10:11:16 | f(...) | $@ | main.rs:10:30:10:39 | source(...) | source(...) |
Expand All @@ -161,3 +182,7 @@ testFailures
| main.rs:111:35:111:35 | a | main.rs:109:13:109:22 | source(...) | main.rs:111:35:111:35 | a | $@ | main.rs:109:13:109:22 | source(...) | source(...) |
| main.rs:112:35:112:35 | a | main.rs:109:13:109:22 | source(...) | main.rs:112:35:112:35 | a | $@ | main.rs:109:13:109:22 | source(...) | source(...) |
| main.rs:113:35:113:35 | a | main.rs:109:13:109:22 | source(...) | main.rs:113:35:113:35 | a | $@ | main.rs:109:13:109:22 | source(...) | source(...) |
| main.rs:121:14:121:25 | await future | main.rs:120:30:120:40 | source(...) | main.rs:121:14:121:25 | await future | $@ | main.rs:120:30:120:40 | source(...) | source(...) |
| main.rs:127:18:127:21 | data | main.rs:125:20:125:30 | source(...) | main.rs:127:18:127:21 | data | $@ | main.rs:125:20:125:30 | source(...) | source(...) |
| main.rs:135:14:135:25 | await future | main.rs:133:20:133:30 | source(...) | main.rs:135:14:135:25 | await future | $@ | main.rs:133:20:133:30 | source(...) | source(...) |
| main.rs:145:14:145:21 | captured | main.rs:142:24:142:34 | source(...) | main.rs:145:14:145:21 | captured | $@ | main.rs:142:24:142:34 | source(...) | source(...) |
56 changes: 56 additions & 0 deletions rust/ql/test/library-tests/dataflow/lambdas/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -113,6 +113,61 @@ fn test_external_call() {
may_invoke_callback4(|x| sink(a)); // $ hasValueFlow=81
}

mod async_blocks {
use super::{sink, source};

async fn async_block_flow_out() {
let future = async { source(206) };
sink(future.await); // $ hasValueFlow=206
}

async fn async_block_flow_in() {
let data = source(207);
async {
sink(data); // $ hasValueFlow=207
}
.await;
}

async fn async_block_flow_through() {
let data = source(208);
let future = async { data };
sink(future.await); // $ hasValueFlow=208
}

async fn async_block_captured_variable() {
let mut captured = 1;
sink(captured);
async {
captured = source(209);
}
.await;
sink(captured); // $ hasValueFlow=209
}

async fn boxed_async_block_captured_variable() {
let mut captured = 1;
sink(captured);
Box::pin(async {
captured = source(210);
})
.await;
sink(captured); // $ MISSING: hasValueFlow=210
}

async fn test_async_blocks() {
async_block_flow_out().await;
async_block_flow_in().await;
async_block_flow_through().await;
async_block_captured_variable().await;
boxed_async_block_captured_variable().await;
}

pub fn main() {
futures::executor::block_on(test_async_blocks());
}
}

fn main() {
closure_flow_out();
closure_flow_in();
Expand All @@ -123,4 +178,5 @@ fn main() {
function_flows_through();
test_apply();
test_apply_wrap();
async_blocks::main();
}
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