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C#: Include all binding expr in data flow analysis. #7893

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C#: Include all binding expr in data flow analysis. #7893

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18 changes: 9 additions & 9 deletions csharp/ql/lib/semmle/code/csharp/Assignable.qll
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Expand Up @@ -281,11 +281,11 @@ module AssignableInternal {
def = TPatternDefinition(result)
}

/** A local variable declaration at the top-level of a pattern. */
class TopLevelPatternDecl extends LocalVariableDeclExpr {
/** A local variable declaration at any level of a pattern. */
class AnyLevelPatternDecl extends LocalVariableDeclExpr {
private PatternMatch pm;

TopLevelPatternDecl() { this = pm.getPattern().(BindingPatternExpr).getVariableDeclExpr() }
AnyLevelPatternDecl() { this = pm.getAPattern().(BindingPatternExpr).getVariableDeclExpr() }

PatternMatch getMatch() { result = pm }
}
Expand All @@ -305,7 +305,7 @@ module AssignableInternal {
TLocalVariableDefinition(LocalVariableDeclExpr lvde) {
not lvde.hasInitializer() and
not exists(getTupleSource(TTupleAssignmentDefinition(_, lvde))) and
not lvde instanceof TopLevelPatternDecl and
not lvde instanceof AnyLevelPatternDecl and
not lvde.isOutArgument()
} or
TImplicitParameterDefinition(Parameter p) {
Expand All @@ -317,7 +317,7 @@ module AssignableInternal {
)
} or
TAddressOfDefinition(AddressOfExpr aoe) or
TPatternDefinition(TopLevelPatternDecl tlpd)
TPatternDefinition(AnyLevelPatternDecl tlpd)

/**
* Gets the source expression assigned in tuple definition `def`, if any.
Expand Down Expand Up @@ -707,15 +707,15 @@ module AssignableDefinitions {
* A local variable definition in a pattern, for example `x is int i`.
*/
class PatternDefinition extends AssignableDefinition, TPatternDefinition {
TopLevelPatternDecl tlpd;
AnyLevelPatternDecl alpd;

PatternDefinition() { this = TPatternDefinition(tlpd) }
PatternDefinition() { this = TPatternDefinition(alpd) }

/** Gets the element matches against this pattern. */
PatternMatch getMatch() { result = tlpd.getMatch() }
PatternMatch getMatch() { result = alpd.getMatch() }

/** Gets the underlying local variable declaration. */
LocalVariableDeclExpr getDeclaration() { result = tlpd }
LocalVariableDeclExpr getDeclaration() { result = alpd }

override Expr getSource() { result = this.getMatch().getExpr() }

Expand Down
4 changes: 4 additions & 0 deletions csharp/ql/lib/semmle/code/csharp/exprs/Expr.qll
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Expand Up @@ -554,10 +554,14 @@ class PatternMatch extends ControlFlowElement, @pattern_match {
/** Gets the pattern of this match. */
PatternExpr getPattern() { none() }

PatternExpr getAPattern() { hasChildPattern(this, result) }

/** Gets the expression that is matched against a pattern. */
Expr getExpr() { none() }
}

private predicate myTest(PatternMatch pm, PatternExpr child) { child = pm.getAPattern() }

/** An `is` expression. */
class IsExpr extends Expr, PatternMatch, @is_expr {
/** Gets the expression being checked, for example `x` in `x is string`. */
Expand Down
2 changes: 1 addition & 1 deletion csharp/ql/test/library-tests/dataflow/patterns/Patterns.cs
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Expand Up @@ -12,7 +12,7 @@ private void M1()
var r = new RecordClass2(o);
if (r is RecordClass2 { Prop: object p })
{
Sink(p); // $ MISSING: hasValueFlow=1
Sink(p); // $ hasValueFlow=1
}
}

Expand Down