Unify incdec-rhs into the compound-rhs node kind

2026-07-31 07:22:56 +02:00 · 2026-07-10 23:52:04 +01:00
parent 6bb4aefa4e
commit 8eaa86ea01
7 changed files with 70 additions and 97 deletions
--- a/go/ql/lib/semmle/go/controlflow/ControlFlowGraphShared.qll
+++ b/go/ql/lib/semmle/go/controlflow/ControlFlowGraphShared.qll
@@ -485,8 +485,6 @@ module GoCfg {
      or
      n instanceof Go::SendStmt
      or
-      n instanceof Go::IncDecStmt
-      or
      n instanceof Go::FuncDecl
    }

@@ -543,8 +541,10 @@ module GoCfg {
          tag = "zero-init:" + i.toString()
        )
        or
-        // Increment/decrement implicit right-hand side (the `operand + 1` value)
-        n instanceof Go::IncDecStmt and tag = "incdec-rhs"
+        // Increment/decrement: a single node computes `operand + 1` (or `- 1`)
+        // and writes it back, modelled the same as a compound assignment's
+        // `compound-rhs` node (see `IR::EvalCompoundAssignRhsInstruction`).
+        n instanceof Go::IncDecStmt and tag = "compound-rhs"
        or
        // Result write nodes in return statements
        exists(int i, Go::ReturnStmt ret |
@@ -1154,26 +1154,23 @@ module GoCfg {
    }

    /**
-     * Increment/decrement: operand → incdec-rhs → In(stmt)
-     * (IncDecStmt is in postOrInOrder, so In(stmt) is its evaluation point)
+     * Increment/decrement: operand → compound-rhs → After(stmt).
     *
-     * The implicit constant `1` operand of the `operand + 1` computation is
-     * modelled directly on the `incdec-rhs` instruction rather than as its own
-     * control-flow node.
+     * `x++` is modelled just like the compound assignment `x += 1`: a single
+     * `compound-rhs` node computes the updated value and writes it back to the
+     * operand (see `IR::EvalCompoundAssignRhsInstruction`). The implicit constant
+     * `1` is modelled directly on that node rather than as its own node.
     */
    private predicate incDecStep(PreControlFlowNode n1, PreControlFlowNode n2) {
      exists(Go::IncDecStmt s |
        // Before → Before operand
        n1.isBefore(s) and n2.isBefore(s.getOperand())
        or
-        // After operand → incdec-rhs
-        n1.isAfter(s.getOperand()) and n2.isAdditional(s, "incdec-rhs")
+        // After operand → compound-rhs (the update value + write)
+        n1.isAfter(s.getOperand()) and n2.isAdditional(s, "compound-rhs")
        or
-        // incdec-rhs → In(stmt) (the assignment itself)
-        n1.isAdditional(s, "incdec-rhs") and n2.isIn(s)
-        or
-        // In(stmt) → After(stmt)
-        n1.isIn(s) and n2.isAfter(s)
+        // compound-rhs → After(stmt)
+        n1.isAdditional(s, "compound-rhs") and n2.isAfter(s)
      )
    }

--- a/go/ql/lib/semmle/go/controlflow/IR.qll
+++ b/go/ql/lib/semmle/go/controlflow/IR.qll
@@ -176,11 +176,6 @@ module IR {
      or
      this instanceof ConditionGuardInstruction and result = "condition guard"
      or
-      this instanceof IncDecInstruction and result = "increment/decrement"
-      or
-      this instanceof EvalIncDecRhsInstruction and
-      result = "right-hand side of increment/decrement"
-      or
      this instanceof ReturnInstruction and result = "return"
      or
      this instanceof WriteResultInstruction and result = "result write"
@@ -665,23 +660,36 @@ module IR {
  }

  /**
-   * An instruction that computes the (implicit) right-hand side of a compound assignment,
-   * such as the `x + y` in `x += y`, and writes the resulting value to the assignment's
-   * left-hand side.
+   * An instruction that computes the (implicit) right-hand side of a compound
+   * assignment (the `x + y` in `x += y`) or an increment/decrement (the
+   * `x + 1` in `x++`), and writes the resulting value to the left-hand side.
   */
  class EvalCompoundAssignRhsInstruction extends WriteInstruction {
-    CompoundAssignStmt assgn;
+    AstNode s;

-    EvalCompoundAssignRhsInstruction() { this.isAdditional(assgn, "compound-rhs") }
+    EvalCompoundAssignRhsInstruction() {
+      this.isAdditional(s, "compound-rhs") and
+      (s instanceof CompoundAssignStmt or s instanceof IncDecStmt)
+    }

-    /** Gets the corresponding compound assignment statement. */
-    CompoundAssignStmt getAssignment() { result = assgn }
+    /** Gets the corresponding compound assignment statement, if it is one. */
+    CompoundAssignStmt getAssignment() { result = s }
+
+    /**
+     * Gets the corresponding compound assignment (`x += y`) or increment/decrement
+     * (`x++`, `x--`) statement.
+     */
+    AstNode getStmt() { result = s }

    override Instruction getRhs() { result = this }

-    override Type getResultType() { result = assgn.getRhs().getType() }
+    override Type getResultType() {
+      result = s.(CompoundAssignStmt).getRhs().getType()
+      or
+      result = s.(IncDecStmt).getOperand().getType()
+    }

-    override ControlFlow::Root getRoot() { result.isRootOf(assgn) }
+    override ControlFlow::Root getRoot() { result.isRootOf(s) }
  }

  /** An instruction extracting a component of a tuple value. */
@@ -871,36 +879,6 @@ module IR {
    override ControlFlow::Root getRoot() { result.isRootOf(go) }
  }

-  /** An instruction that corresponds to an increment or decrement statement. */
-  class IncDecInstruction extends WriteInstruction {
-    IncDecStmt ids;
-
-    IncDecInstruction() { this.isIn(ids) }
-
-    override Instruction getRhs() {
-      result.(EvalIncDecRhsInstruction).isAdditional(ids, "incdec-rhs")
-    }
-
-    override ControlFlow::Root getRoot() { result.isRootOf(ids) }
-  }
-
-  /**
-   * An instruction that computes the (implicit) right-hand side of an increment or
-   * decrement statement.
-   */
-  class EvalIncDecRhsInstruction extends Instruction {
-    IncDecStmt ids;
-
-    EvalIncDecRhsInstruction() { this.isAdditional(ids, "incdec-rhs") }
-
-    /** Gets the corresponding increment or decrement statement. */
-    IncDecStmt getStmt() { result = ids }
-
-    override Type getResultType() { result = ids.getOperand().getType() }
-
-    override ControlFlow::Root getRoot() { result.isRootOf(ids) }
-  }
-
  /** An instruction corresponding to a return from a function. */
  class ReturnInstruction extends Instruction {
    ReturnStmt ret;
@@ -1104,12 +1082,14 @@ module IR {
        )
      )
      or
-      exists(IncDecStmt ids | write.isIn(ids) | lhs = ids.getOperand().stripParens())
-      or
      exists(CompoundAssignStmt ca | write.isAdditional(ca, "compound-rhs") |
        lhs = ca.getLhs().stripParens()
      )
      or
+      exists(IncDecStmt ids | write.isAdditional(ids, "compound-rhs") |
+        lhs = ids.getOperand().stripParens()
+      )
+      or
      exists(FuncDef fd, int idx |
        write.isAdditional(fd.getBody(), "param-init:" + idx.toString()) and
        lhs = fd.getParameter(idx).getDeclaration()
--- a/go/ql/src/experimental/IntegerOverflow/RangeAnalysis.qll
+++ b/go/ql/src/experimental/IntegerOverflow/RangeAnalysis.qll
@@ -389,12 +389,13 @@ float getAnSsaUpperBound(SsaDefinition def) {
        )
      else
        //SSA definition corresponding to an `IncDecStmt`
-        if explicitDef.getInstruction() instanceof IR::IncDecInstruction
+        if
+          explicitDef.getInstruction().(IR::EvalCompoundAssignRhsInstruction).getStmt() instanceof
+            IncDecStmt
        then
-          exists(IncDecStmt incOrDec, IR::IncDecInstruction instr, float exprLB |
-            instr = explicitDef.getInstruction() and
+          exists(IncDecStmt incOrDec, float exprLB |
+            explicitDef.getInstruction().(IR::EvalCompoundAssignRhsInstruction).getStmt() = incOrDec and
            exprLB = getAnUpperBound(incOrDec.getOperand()) and
-            instr.getRhs().(IR::EvalIncDecRhsInstruction).getStmt() = incOrDec and
            (
              //IncStmt(x++)
              exists(IncStmt inc |
@@ -475,12 +476,13 @@ float getAnSsaLowerBound(SsaDefinition def) {
        )
      else
        //IncDecStmt
-        if explicitDef.getInstruction() instanceof IR::IncDecInstruction
+        if
+          explicitDef.getInstruction().(IR::EvalCompoundAssignRhsInstruction).getStmt() instanceof
+            IncDecStmt
        then
-          exists(IncDecStmt incOrDec, IR::IncDecInstruction instr, float exprLB |
-            instr = explicitDef.getInstruction() and
+          exists(IncDecStmt incOrDec, float exprLB |
+            explicitDef.getInstruction().(IR::EvalCompoundAssignRhsInstruction).getStmt() = incOrDec and
            exprLB = getALowerBound(incOrDec.getOperand()) and
-            instr.getRhs().(IR::EvalIncDecRhsInstruction).getStmt() = incOrDec and
            (
              //IncStmt(x++)
              exists(IncStmt inc |
@@ -550,9 +552,7 @@ predicate ssaDependsOnSsa(SsaDefinition nextDef, SsaDefinition prevDef) {
    nextDef
        .(SsaExplicitDefinition)
        .getInstruction()
-        .(IR::IncDecInstruction)
-        .getRhs()
-        .(IR::EvalIncDecRhsInstruction)
+        .(IR::EvalCompoundAssignRhsInstruction)
        .getStmt() = incDec and
    ssaDependsOnExpr(prevDef, incDec.getOperand())
  )
--- a/go/ql/test/library-tests/semmle/go/controlflow/ControlFlowGraph/ControlFlowNode_getASuccessor.expected
+++ b/go/ql/test/library-tests/semmle/go/controlflow/ControlFlowGraph/ControlFlowNode_getASuccessor.expected
@@ -1279,7 +1279,7 @@
 | exprs.go:49:30:54:1 | result-read:0 block statement | exprs.go:49:1:54:1 | Normal Exit |
 | exprs.go:49:30:54:1 | zero-init:0 block statement | exprs.go:50:2:52:2 | for statement |
 | exprs.go:50:2:52:2 | After for statement | exprs.go:53:2:53:7 | Before return statement |
-| exprs.go:50:2:52:2 | [LoopHeader] for statement | exprs.go:50:27:50:29 | Before increment statement |
+| exprs.go:50:2:52:2 | [LoopHeader] for statement | exprs.go:50:27:50:29 | increment statement |
 | exprs.go:50:2:52:2 | for statement | exprs.go:50:6:50:11 | ... := ... |
 | exprs.go:50:6:50:11 | ... := ... | exprs.go:50:11:50:11 | Before 0 |
 | exprs.go:50:6:50:11 | After ... := ... | exprs.go:50:14:50:24 | Before ...<... |
@@ -1304,13 +1304,12 @@
 | exprs.go:50:22:50:23 | After xs | exprs.go:50:18:50:24 | call to len |
 | exprs.go:50:22:50:23 | Before xs | exprs.go:50:22:50:23 | xs |
 | exprs.go:50:22:50:23 | xs | exprs.go:50:22:50:23 | After xs |
-| exprs.go:50:27:50:27 | After i | exprs.go:50:27:50:29 | incdec-rhs increment statement |
+| exprs.go:50:27:50:27 | After i | exprs.go:50:27:50:29 | compound-rhs increment statement |
 | exprs.go:50:27:50:27 | Before i | exprs.go:50:27:50:27 | i |
 | exprs.go:50:27:50:27 | i | exprs.go:50:27:50:27 | After i |
 | exprs.go:50:27:50:29 | After increment statement | exprs.go:50:14:50:24 | Before ...<... |
-| exprs.go:50:27:50:29 | Before increment statement | exprs.go:50:27:50:27 | Before i |
-| exprs.go:50:27:50:29 | incdec-rhs increment statement | exprs.go:50:27:50:29 | increment statement |
-| exprs.go:50:27:50:29 | increment statement | exprs.go:50:27:50:29 | After increment statement |
+| exprs.go:50:27:50:29 | compound-rhs increment statement | exprs.go:50:27:50:29 | After increment statement |
+| exprs.go:50:27:50:29 | increment statement | exprs.go:50:27:50:27 | Before i |
 | exprs.go:50:31:52:2 | After block statement | exprs.go:50:2:52:2 | [LoopHeader] for statement |
 | exprs.go:50:31:52:2 | block statement | exprs.go:51:3:51:14 | ... += ... |
 | exprs.go:51:3:51:5 | After res | exprs.go:51:10:51:14 | Before index expression |
@@ -2235,7 +2234,7 @@
 | main.go:73:7:73:7 | After 1 | main.go:73:2:73:7 | assign:0 ... := ... |
 | main.go:73:7:73:7 | Before 1 | main.go:73:7:73:7 | 1 |
 | main.go:74:2:79:2 | After for statement | main.go:80:2:80:13 | expression statement |
-| main.go:74:2:79:2 | [LoopHeader] for statement | main.go:74:16:74:18 | Before increment statement |
+| main.go:74:2:79:2 | [LoopHeader] for statement | main.go:74:16:74:18 | increment statement |
 | main.go:74:2:79:2 | for statement | main.go:74:6:74:11 | ... := ... |
 | main.go:74:6:74:11 | ... := ... | main.go:74:11:74:11 | Before 0 |
 | main.go:74:6:74:11 | After ... := ... | main.go:74:20:79:2 | block statement |
@@ -2243,13 +2242,12 @@
 | main.go:74:11:74:11 | 0 | main.go:74:11:74:11 | After 0 |
 | main.go:74:11:74:11 | After 0 | main.go:74:6:74:11 | assign:0 ... := ... |
 | main.go:74:11:74:11 | Before 0 | main.go:74:11:74:11 | 0 |
-| main.go:74:16:74:16 | After i | main.go:74:16:74:18 | incdec-rhs increment statement |
+| main.go:74:16:74:16 | After i | main.go:74:16:74:18 | compound-rhs increment statement |
 | main.go:74:16:74:16 | Before i | main.go:74:16:74:16 | i |
 | main.go:74:16:74:16 | i | main.go:74:16:74:16 | After i |
 | main.go:74:16:74:18 | After increment statement | main.go:74:20:79:2 | block statement |
-| main.go:74:16:74:18 | Before increment statement | main.go:74:16:74:16 | Before i |
-| main.go:74:16:74:18 | incdec-rhs increment statement | main.go:74:16:74:18 | increment statement |
-| main.go:74:16:74:18 | increment statement | main.go:74:16:74:18 | After increment statement |
+| main.go:74:16:74:18 | compound-rhs increment statement | main.go:74:16:74:18 | After increment statement |
+| main.go:74:16:74:18 | increment statement | main.go:74:16:74:16 | Before i |
 | main.go:74:20:79:2 | After block statement | main.go:74:2:79:2 | [LoopHeader] for statement |
 | main.go:74:20:79:2 | block statement | main.go:75:3:77:3 | if statement |
 | main.go:75:3:77:3 | After if statement | main.go:78:3:78:7 | ... = ... |
@@ -2291,7 +2289,7 @@
 | main.go:82:7:82:7 | After 1 | main.go:82:2:82:7 | assign:0 ... := ... |
 | main.go:82:7:82:7 | Before 1 | main.go:82:7:82:7 | 1 |
 | main.go:83:2:88:2 | After for statement | main.go:89:2:89:13 | expression statement |
-| main.go:83:2:88:2 | [LoopHeader] for statement | main.go:83:16:83:18 | Before increment statement |
+| main.go:83:2:88:2 | [LoopHeader] for statement | main.go:83:16:83:18 | increment statement |
 | main.go:83:2:88:2 | for statement | main.go:83:6:83:11 | ... := ... |
 | main.go:83:6:83:11 | ... := ... | main.go:83:11:83:11 | Before 0 |
 | main.go:83:6:83:11 | After ... := ... | main.go:83:20:88:2 | block statement |
@@ -2299,13 +2297,12 @@
 | main.go:83:11:83:11 | 0 | main.go:83:11:83:11 | After 0 |
 | main.go:83:11:83:11 | After 0 | main.go:83:6:83:11 | assign:0 ... := ... |
 | main.go:83:11:83:11 | Before 0 | main.go:83:11:83:11 | 0 |
-| main.go:83:16:83:16 | After i | main.go:83:16:83:18 | incdec-rhs increment statement |
+| main.go:83:16:83:16 | After i | main.go:83:16:83:18 | compound-rhs increment statement |
 | main.go:83:16:83:16 | Before i | main.go:83:16:83:16 | i |
 | main.go:83:16:83:16 | i | main.go:83:16:83:16 | After i |
 | main.go:83:16:83:18 | After increment statement | main.go:83:20:88:2 | block statement |
-| main.go:83:16:83:18 | Before increment statement | main.go:83:16:83:16 | Before i |
-| main.go:83:16:83:18 | incdec-rhs increment statement | main.go:83:16:83:18 | increment statement |
-| main.go:83:16:83:18 | increment statement | main.go:83:16:83:18 | After increment statement |
+| main.go:83:16:83:18 | compound-rhs increment statement | main.go:83:16:83:18 | After increment statement |
+| main.go:83:16:83:18 | increment statement | main.go:83:16:83:16 | Before i |
 | main.go:83:20:88:2 | After block statement | main.go:83:2:88:2 | [LoopHeader] for statement |
 | main.go:83:20:88:2 | block statement | main.go:84:3:84:7 | ... = ... |
 | main.go:84:3:84:7 | ... = ... | main.go:84:7:84:7 | Before 2 |
@@ -3160,7 +3157,7 @@
 | stmts.go:23:11:37:2 | After block statement | stmts.go:23:2:37:2 | [LoopHeader] for statement |
 | stmts.go:23:11:37:2 | block statement | stmts.go:24:3:36:3 | for statement |
 | stmts.go:24:3:36:3 | After for statement | stmts.go:23:11:37:2 | After block statement |
-| stmts.go:24:3:36:3 | [LoopHeader] for statement | stmts.go:24:23:24:25 | Before increment statement |
+| stmts.go:24:3:36:3 | [LoopHeader] for statement | stmts.go:24:23:24:25 | increment statement |
 | stmts.go:24:3:36:3 | for statement | stmts.go:24:7:24:12 | ... := ... |
 | stmts.go:24:7:24:12 | ... := ... | stmts.go:24:12:24:12 | Before 0 |
 | stmts.go:24:7:24:12 | After ... := ... | stmts.go:24:15:24:20 | Before ...<... |
@@ -3179,13 +3176,12 @@
 | stmts.go:24:19:24:20 | 10 | stmts.go:24:19:24:20 | After 10 |
 | stmts.go:24:19:24:20 | After 10 | stmts.go:24:15:24:20 | ...<... |
 | stmts.go:24:19:24:20 | Before 10 | stmts.go:24:19:24:20 | 10 |
-| stmts.go:24:23:24:23 | After i | stmts.go:24:23:24:25 | incdec-rhs increment statement |
+| stmts.go:24:23:24:23 | After i | stmts.go:24:23:24:25 | compound-rhs increment statement |
 | stmts.go:24:23:24:23 | Before i | stmts.go:24:23:24:23 | i |
 | stmts.go:24:23:24:23 | i | stmts.go:24:23:24:23 | After i |
 | stmts.go:24:23:24:25 | After increment statement | stmts.go:24:15:24:20 | Before ...<... |
-| stmts.go:24:23:24:25 | Before increment statement | stmts.go:24:23:24:23 | Before i |
-| stmts.go:24:23:24:25 | incdec-rhs increment statement | stmts.go:24:23:24:25 | increment statement |
-| stmts.go:24:23:24:25 | increment statement | stmts.go:24:23:24:25 | After increment statement |
+| stmts.go:24:23:24:25 | compound-rhs increment statement | stmts.go:24:23:24:25 | After increment statement |
+| stmts.go:24:23:24:25 | increment statement | stmts.go:24:23:24:23 | Before i |
 | stmts.go:24:27:36:3 | block statement | stmts.go:25:4:35:4 | if statement |
 | stmts.go:25:4:35:4 | if statement | stmts.go:25:7:25:16 | ... := ... |
 | stmts.go:25:7:25:16 | ... := ... | stmts.go:25:12:25:16 | Before ...-... |
--- a/go/ql/test/library-tests/semmle/go/dataflow/FlowSteps/LocalFlowStep.expected
+++ b/go/ql/test/library-tests/semmle/go/dataflow/FlowSteps/LocalFlowStep.expected
@@ -20,7 +20,7 @@
 | main.go:15:9:15:9 | 0 | main.go:15:2:15:9 | SSA def(acc) |
 | main.go:16:9:19:2 | SSA def(acc) | main.go:17:3:17:5 | acc |
 | main.go:17:3:17:7 | SSA def(acc) | main.go:18:10:18:12 | acc |
-| main.go:17:3:17:7 | incdec-rhs increment statement | main.go:17:3:17:7 | SSA def(acc) |
+| main.go:17:3:17:7 | compound-rhs increment statement | main.go:17:3:17:7 | SSA def(acc) |
 | main.go:22:42:31:1 | SSA def(b) | main.go:23:5:23:5 | b |
 | main.go:22:42:31:1 | SSA def(x) | main.go:24:10:24:10 | x |
 | main.go:22:42:31:1 | SSA def(x) | main.go:26:11:26:11 | x |
--- a/go/ql/test/library-tests/semmle/go/dataflow/FunctionInputsAndOutputs/FunctionOutput_getEntryNode.expected
+++ b/go/ql/test/library-tests/semmle/go/dataflow/FunctionInputsAndOutputs/FunctionOutput_getEntryNode.expected
@@ -16,7 +16,7 @@
 | result 1 | main.go:35:1:38:1 | function declaration | main.go:35:29:38:1 | zero-init:1 block statement |
 | result 1 | main.go:35:1:38:1 | function declaration | main.go:36:9:36:10 | 42 |
 | result 1 | main.go:40:1:48:1 | function declaration | main.go:40:33:48:1 | zero-init:1 block statement |
-| result 1 | main.go:40:1:48:1 | function declaration | main.go:42:3:42:5 | incdec-rhs increment statement |
+| result 1 | main.go:40:1:48:1 | function declaration | main.go:42:3:42:5 | compound-rhs increment statement |
 | result 1 | main.go:40:1:48:1 | function declaration | main.go:45:13:45:13 | 1 |
 | result 1 | main.go:40:1:48:1 | function declaration | main.go:47:12:47:12 | 4 |
 | result 1 | tst2.go:8:1:12:1 | function declaration | tst2.go:11:12:11:14 | err |
--- a/go/ql/test/library-tests/semmle/go/dataflow/SSA/VarDefs.expected
+++ b/go/ql/test/library-tests/semmle/go/dataflow/SSA/VarDefs.expected
@@ -17,11 +17,11 @@
 | main.go:59:3:59:7 | assign:0 ... = ... | main.go:57:6:57:6 | x | main.go:59:7:59:7 | 2 |
 | main.go:63:2:63:7 | assign:0 ... := ... | main.go:63:2:63:2 | y | main.go:63:7:63:7 | 1 |
 | main.go:64:6:64:11 | assign:0 ... := ... | main.go:64:6:64:6 | i | main.go:64:11:64:11 | 0 |
-| main.go:64:16:64:18 | increment statement | main.go:64:6:64:6 | i | main.go:64:16:64:18 | incdec-rhs increment statement |
+| main.go:64:16:64:18 | compound-rhs increment statement | main.go:64:6:64:6 | i | main.go:64:16:64:18 | compound-rhs increment statement |
 | main.go:68:3:68:7 | assign:0 ... = ... | main.go:63:2:63:2 | y | main.go:68:7:68:7 | 2 |
 | main.go:72:2:72:7 | assign:0 ... := ... | main.go:72:2:72:2 | z | main.go:72:7:72:7 | 1 |
 | main.go:73:6:73:11 | assign:0 ... := ... | main.go:73:6:73:6 | i | main.go:73:11:73:11 | 0 |
-| main.go:73:16:73:18 | increment statement | main.go:73:6:73:6 | i | main.go:73:16:73:18 | incdec-rhs increment statement |
+| main.go:73:16:73:18 | compound-rhs increment statement | main.go:73:6:73:6 | i | main.go:73:16:73:18 | compound-rhs increment statement |
 | main.go:74:3:74:7 | assign:0 ... = ... | main.go:72:2:72:2 | z | main.go:74:7:74:7 | 2 |
 | main.go:82:36:86:1 | zero-init:0 block statement | main.go:82:18:82:18 | a | main.go:82:36:86:1 | zero-init:0 block statement |
 | main.go:82:36:86:1 | zero-init:1 block statement | main.go:82:25:82:25 | b | main.go:82:36:86:1 | zero-init:1 block statement |