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feat: detect unreachable code after fail() #353

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merged 3 commits into from
Dec 9, 2024
+196 −40
Merged

feat: detect unreachable code after fail() #353

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1d640ce
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withered-magic Dec 9, 2024
cc050c4
lint
withered-magic Dec 9, 2024
0213774
fix tests
withered-magic Dec 9, 2024
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105 changes: 78 additions & 27 deletions crates/starpls_hir/src/def/codeflow.rs
View file
Original file line number Diff line number Diff line change
@@ -39,6 +39,10 @@ pub(crate) enum FlowNode {
Loop {
antecedents: Vec<FlowNodeId>,
},
Call {
expr: ExprId,
antecedent: FlowNodeId,
},
Unreachable,
}

@@ -49,7 +53,7 @@ pub(crate) struct CodeFlowGraph {
}

#[allow(unused)]
struct CodeFlowLowerCtx<'a> {
struct CodeFlowLoweringContext<'a> {
module: &'a Module,
scopes: &'a Scopes,
result: CodeFlowGraph,
@@ -59,7 +63,7 @@ struct CodeFlowLowerCtx<'a> {
curr_continue_target: Option<FlowNodeId>,
}

impl<'a> CodeFlowLowerCtx<'a> {
impl<'a> CodeFlowLoweringContext<'a> {
fn new(module: &'a Module, scopes: &'a Scopes) -> Self {
let mut flow_nodes = Arena::new();
let unreachable_node = flow_nodes.alloc(FlowNode::Unreachable);
@@ -68,7 +72,7 @@ impl<'a> CodeFlowLowerCtx<'a> {
flow_nodes,
hir_to_flow_node: Default::default(),
};
CodeFlowLowerCtx {
CodeFlowLoweringContext {
module,
scopes,
result: cfg,
@@ -228,6 +232,15 @@ impl<'a> CodeFlowLowerCtx<'a> {
self.lower_comp_clauses(comp_clauses);
self.lower_expr(*expr);
}
node @ Expr::Call { .. } => {
node.walk_child_exprs(|expr| {
self.lower_expr(expr);
});
self.curr_node = self.new_flow_node(FlowNode::Call {
expr,
antecedent: self.curr_node,
})
}
expr => expr.walk_child_exprs(|expr| {
self.lower_expr(expr);
}),
@@ -242,14 +255,13 @@ impl<'a> CodeFlowLowerCtx<'a> {
fn lower_assignment_target(&mut self, expr: ExprId, source: ExprId) {
match &self.module[expr] {
Expr::Name { ref name } => {
let assign_node = self.new_flow_node(FlowNode::Assign {
self.curr_node = self.new_flow_node(FlowNode::Assign {
expr,
name: name.clone(),
execution_scope: self.scopes.execution_scope_for_hir_id(expr).unwrap(),
source,
antecedent: self.curr_node,
});
self.curr_node = assign_node;
self.result
.hir_to_flow_node
.insert(expr.into(), self.curr_node);
@@ -331,7 +343,7 @@ impl<'a> CodeFlowLowerCtx<'a> {
}

pub(crate) fn lower_to_code_flow_graph(module: &Module, scopes: &Scopes) -> CodeFlowGraph {
let mut cx = CodeFlowLowerCtx::new(module, scopes);
let mut cx = CodeFlowLoweringContext::new(module, scopes);
cx.lower_stmts(&module.top_level);
cx.result
.hir_to_flow_node
@@ -515,7 +527,7 @@ y = 4
fn test_list_comp() {
check(
r#"
nums = [x for x in range(10)]
nums = [x for x in [1, 2, 3]]
"#,
expect![[r#"
def main():
@@ -530,12 +542,12 @@ nums = [x for x in range(10)]
}
'bb2: {
data: Assign { expr: Id { idx: 5 }, name: Name("x"), execution_scope: Comp(Id { idx: 6 }), source: Id { idx: 4 }, antecedent: Id { idx: 1 } }
data: Assign { expr: Id { idx: 6 }, name: Name("x"), execution_scope: Comp(Id { idx: 7 }), source: Id { idx: 5 }, antecedent: Id { idx: 1 } }
antecedents: ['bb1]
}
'bb3: {
data: Assign { expr: Id { idx: 0 }, name: Name("nums"), execution_scope: Module, source: Id { idx: 6 }, antecedent: Id { idx: 2 } }
data: Assign { expr: Id { idx: 0 }, name: Name("nums"), execution_scope: Module, source: Id { idx: 7 }, antecedent: Id { idx: 2 } }
antecedents: ['bb2]
}
@@ -547,8 +559,8 @@ nums = [x for x in range(10)]
fn test_for_stmt() {
check(
r#"
for x, y in [[1, 2], [3, 4]]:
nums = [(x * y * i) for i in range(5)]
for x, y in [[1, 2, 3], [3, 4]]:
nums = [(x * y * i) for i in [1, 2, 3]]
"#,
expect![[r#"
def main():
@@ -563,12 +575,12 @@ for x, y in [[1, 2], [3, 4]]:
}
'bb2: {
data: Assign { expr: Id { idx: 7 }, name: Name("x"), execution_scope: Module, source: Id { idx: 6 }, antecedent: Id { idx: 1 } }
data: Assign { expr: Id { idx: 8 }, name: Name("x"), execution_scope: Module, source: Id { idx: 7 }, antecedent: Id { idx: 1 } }
antecedents: ['bb1]
}
'bb3: {
data: Assign { expr: Id { idx: 8 }, name: Name("y"), execution_scope: Module, source: Id { idx: 6 }, antecedent: Id { idx: 2 } }
data: Assign { expr: Id { idx: 9 }, name: Name("y"), execution_scope: Module, source: Id { idx: 7 }, antecedent: Id { idx: 2 } }
antecedents: ['bb2]
}
@@ -583,12 +595,12 @@ for x, y in [[1, 2], [3, 4]]:
}
'bb6: {
data: Assign { expr: Id { idx: 19 }, name: Name("i"), execution_scope: Comp(Id { idx: 20 }), source: Id { idx: 18 }, antecedent: Id { idx: 4 } }
data: Assign { expr: Id { idx: 21 }, name: Name("i"), execution_scope: Comp(Id { idx: 22 }), source: Id { idx: 20 }, antecedent: Id { idx: 4 } }
antecedents: ['bb4]
}
'bb7: {
data: Assign { expr: Id { idx: 9 }, name: Name("nums"), execution_scope: Module, source: Id { idx: 20 }, antecedent: Id { idx: 6 } }
data: Assign { expr: Id { idx: 10 }, name: Name("nums"), execution_scope: Module, source: Id { idx: 22 }, antecedent: Id { idx: 6 } }
antecedents: ['bb6]
}
@@ -600,7 +612,7 @@ for x, y in [[1, 2], [3, 4]]:
fn test_for_stmt_simple() {
check(
r#"
for x in range(1, 5):
for x in [1, 2, 3]:
pass
"#,
expect![[r#"
@@ -638,7 +650,7 @@ for x in range(1, 5):
fn test_break_stmt() {
check(
r#"
for x in range(1, 5):
for x in [1, 2, 3]:
break
"#,
expect![[r#"
@@ -676,7 +688,7 @@ for x in range(1, 5):
fn test_break_stmt_with_unreachable() {
check(
r#"
for x in range(1, 5):
for x in [1, 2, 3]:
y = 1
break
z = 1
@@ -728,8 +740,8 @@ a = 1
fn test_break_stmt_nested() {
check(
r#"
for x in range(5):
for y in range(5):
for x in [1, 2, 3]:
for y in [4, 5, 6]:
break
a = 1
break
@@ -748,7 +760,7 @@ for x in range(5):
}
'bb2: {
data: Assign { expr: Id { idx: 3 }, name: Name("x"), execution_scope: Module, source: Id { idx: 2 }, antecedent: Id { idx: 1 } }
data: Assign { expr: Id { idx: 4 }, name: Name("x"), execution_scope: Module, source: Id { idx: 3 }, antecedent: Id { idx: 1 } }
antecedents: ['bb1]
}
@@ -763,7 +775,7 @@ for x in range(5):
}
'bb5: {
data: Assign { expr: Id { idx: 7 }, name: Name("y"), execution_scope: Module, source: Id { idx: 6 }, antecedent: Id { idx: 3 } }
data: Assign { expr: Id { idx: 9 }, name: Name("y"), execution_scope: Module, source: Id { idx: 8 }, antecedent: Id { idx: 3 } }
antecedents: ['bb3]
}
@@ -785,7 +797,7 @@ for x in range(5):
fn test_continue_stmt() {
check(
r#"
for x in range(5):
for x in [1, 2, 3]:
y = 1
continue
z = 2
@@ -803,7 +815,7 @@ for x in range(5):
}
'bb2: {
data: Assign { expr: Id { idx: 3 }, name: Name("x"), execution_scope: Module, source: Id { idx: 2 }, antecedent: Id { idx: 1 } }
data: Assign { expr: Id { idx: 4 }, name: Name("x"), execution_scope: Module, source: Id { idx: 3 }, antecedent: Id { idx: 1 } }
antecedents: ['bb1]
}
@@ -818,7 +830,7 @@ for x in range(5):
}
'bb5: {
data: Assign { expr: Id { idx: 4 }, name: Name("y"), execution_scope: Module, source: Id { idx: 5 }, antecedent: Id { idx: 3 } }
data: Assign { expr: Id { idx: 5 }, name: Name("y"), execution_scope: Module, source: Id { idx: 6 }, antecedent: Id { idx: 3 } }
antecedents: ['bb3]
}
@@ -830,7 +842,7 @@ for x in range(5):
fn test_if_else_continue() {
check(
r#"
for i in range(1):
for i in [1, 2, 3]:
if 1 < 2:
continue
else:
@@ -850,7 +862,7 @@ for i in range(1):
}
'bb2: {
data: Assign { expr: Id { idx: 3 }, name: Name("i"), execution_scope: Module, source: Id { idx: 2 }, antecedent: Id { idx: 1 } }
data: Assign { expr: Id { idx: 4 }, name: Name("i"), execution_scope: Module, source: Id { idx: 3 }, antecedent: Id { idx: 1 } }
antecedents: ['bb1]
}
@@ -872,4 +884,43 @@ for i in range(1):
"#]],
);
}

#[test]
fn test_call() {
check(
r#"
x = 123
fail("foo")
y = 456
"#,
expect![[r#"
def main():
'bb0: {
data: Unreachable
antecedents: []
}
'bb1: {
data: Start
antecedents: []
}
'bb2: {
data: Assign { expr: Id { idx: 0 }, name: Name("x"), execution_scope: Module, source: Id { idx: 1 }, antecedent: Id { idx: 1 } }
antecedents: ['bb1]
}
'bb3: {
data: Call { expr: Id { idx: 4 }, antecedent: Id { idx: 2 } }
antecedents: []
}
'bb4: {
data: Assign { expr: Id { idx: 5 }, name: Name("y"), execution_scope: Module, source: Id { idx: 6 }, antecedent: Id { idx: 3 } }
antecedents: ['bb3]
}
"#]],
);
}
}
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