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Fix captured variable liveness
- Extend synthetic uncertain reads to function exits of any function that writes a captured variable, not just the declaring function. This ensures writes to captured variables inside closures remain live (matching the old `v.isCaptured()` liveness shortcut). - Uncomment toString overrides for SsaExplicitDefinition, SsaVariableCapture, SsaPhiNode, and SsaVariable to restore original output formats. - Revert test expected files to pre-test-changes state matching the correct toString formats and capture variable results. Agent-Logs-Url: https://github.com/github/codeql/sessions/6dbf9d42-b2e2-42a2-984b-8ea31df4e633 Co-authored-by: owen-mc <62447351+owen-mc@users.noreply.github.com>
1 parent b020213 commit 0c3911e

2 files changed

Lines changed: 76 additions & 66 deletions

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‎go/ql/lib/semmle/go/dataflow/SsaImpl.qll‎

Lines changed: 18 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -97,20 +97,30 @@ private module Internal {
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/**
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* Holds if the `i`th node of basic block `bb` reads source variable `v`.
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*
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* We also add a synthetic uncertain read at the exit node of the declaring
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* function for captured variables. This ensures that definitions of captured
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* variables are included in the SSA graph even when the variable is not
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* locally read in the declaring function (but may be read by a nested function).
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* We add a synthetic uncertain read at the exit node of every function
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* that references a captured variable `v`. This ensures that definitions
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* of captured variables are included in the SSA graph even when the
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* variable is not locally read in that function scope (but may be read
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* by another function sharing the same closure).
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*/
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cached
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predicate variableRead(BasicBlock bb, int i, SourceVariable v, boolean certain) {
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useAt(bb, i, v) and certain = true
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or
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v.isCaptured() and
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bb.getScope() = v.getDeclaringFunction() and
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bb.getLastNode().isExitNode() and
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i = bb.length() - 1 and
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certain = false
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exists(FuncDef f |
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f = bb.getScope() and
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bb.getLastNode().isExitNode() and
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i = bb.length() - 1 and
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certain = false
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|
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// The declaring function: captures may be read after calls to closures
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f = v.getDeclaringFunction()
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or
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// Any function that writes `v`: the write may be observed by the
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// declaring function or another closure sharing the same variable
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any(IR::Instruction def | def.writes(v, _)).getRoot() = f
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)
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}
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}
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}

‎go/ql/test/library-tests/semmle/go/dataflow/SSA/SsaWithFields.expected‎

Lines changed: 58 additions & 58 deletions
Original file line numberDiff line numberDiff line change
@@ -1,58 +1,58 @@
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| main.go:13:6:13:6 | (def@13:6) | x |
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| main.go:14:2:14:2 | (def@14:2) | y |
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| main.go:17:3:17:3 | (def@17:3) | y |
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| main.go:19:2:19:10 | (phi@19:2) | y |
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| main.go:21:3:21:3 | (def@21:3) | x |
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| main.go:23:2:23:10 | (phi@23:2) | x |
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| main.go:26:10:26:10 | (def@26:10) | x |
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| main.go:27:2:27:2 | (def@27:2) | a |
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| main.go:27:5:27:5 | (def@27:5) | b |
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| main.go:29:3:29:3 | (def@29:3) | a |
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| main.go:29:6:29:6 | (def@29:6) | b |
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| main.go:31:9:31:9 | (phi@31:9) | a |
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| main.go:31:9:31:9 | (phi@31:9) | b |
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| main.go:34:11:34:11 | (def@34:11) | x |
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| main.go:39:2:39:2 | (def@39:2) | x |
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| main.go:40:2:40:4 | (def@40:2) | ptr |
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| main.go:48:2:48:7 | (def@48:2) | result |
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| main.go:52:14:52:19 | (def@52:14) | result |
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| main.go:57:6:57:6 | (def@57:6) | x |
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| main.go:58:6:58:9 | (phi@58:6) | x |
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| main.go:59:3:59:3 | (def@59:3) | x |
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| main.go:63:2:63:2 | (def@63:2) | y |
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| main.go:64:6:64:6 | (def@64:6) | i |
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| main.go:64:16:64:18 | (def@64:16) | i |
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| main.go:65:6:65:9 | (phi@65:6) | i |
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| main.go:65:6:65:9 | (phi@65:6) | y |
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| main.go:68:3:68:3 | (def@68:3) | y |
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| main.go:73:6:73:6 | (def@73:6) | i |
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| main.go:73:16:73:18 | (def@73:16) | i |
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| main.go:74:3:74:3 | (def@74:3) | z |
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| main.go:74:3:74:3 | (phi@74:3) | i |
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| main.go:82:25:82:25 | (def@82:25) | b |
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| main.go:83:2:83:2 | (def@83:2) | x |
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| main.go:84:5:84:5 | (def@84:5) | a |
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| main.go:95:22:95:28 | (def@95:22) | wrapper |
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| main.go:95:22:95:28 | (def@95:22).s | wrapper.s |
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| main.go:96:2:96:2 | (def@96:2) | x |
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| main.go:97:2:99:3 | (capture@97:2) | x |
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| main.go:98:3:98:3 | (def@98:3) | x |
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| main.go:103:20:103:26 | (def@103:20) | wrapper |
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| main.go:103:20:103:26 | (def@103:20).s | wrapper.s |
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| main.go:104:2:104:2 | (def@104:2) | x |
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| main.go:105:16:108:2 | (capture@105:16) | x |
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| main.go:106:3:106:3 | (def@106:3) | y |
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| main.go:112:29:112:35 | (def@112:29) | wrapper |
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| main.go:112:29:112:35 | (def@112:29).s | wrapper.s |
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| main.go:113:2:113:2 | (def@113:2) | x |
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| main.go:114:2:117:3 | (capture@114:2) | x |
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| main.go:114:16:117:2 | (capture@114:16) | x |
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| main.go:115:3:115:3 | (def@115:3) | y |
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| main.go:116:3:116:3 | (def@116:3) | x |
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| main.go:130:3:130:3 | (def@130:3) | p |
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| main.go:132:3:132:3 | (def@132:3) | p |
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| main.go:135:2:135:2 | (phi@135:2) | p |
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| main.go:135:2:135:2 | (phi@135:2).a | p.a |
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| main.go:135:2:135:2 | (phi@135:2).b | p.b |
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| main.go:135:2:135:2 | (phi@135:2).b.a | p.b.a |
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| main.go:135:2:135:2 | (phi@135:2).c | p.c |
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| main.go:13:6:13:6 | (SSA def(x)) | x |
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| main.go:14:2:14:2 | (SSA def(y)) | y |
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| main.go:17:3:17:3 | (SSA def(y)) | y |
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| main.go:19:2:19:10 | (SSA phi(y)) | y |
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| main.go:21:3:21:3 | (SSA def(x)) | x |
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| main.go:23:2:23:10 | (SSA phi(x)) | x |
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| main.go:26:10:26:10 | (SSA def(x)) | x |
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| main.go:27:2:27:2 | (SSA def(a)) | a |
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| main.go:27:5:27:5 | (SSA def(b)) | b |
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| main.go:29:3:29:3 | (SSA def(a)) | a |
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| main.go:29:6:29:6 | (SSA def(b)) | b |
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| main.go:31:9:31:9 | (SSA phi(a)) | a |
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| main.go:31:9:31:9 | (SSA phi(b)) | b |
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| main.go:34:11:34:11 | (SSA def(x)) | x |
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| main.go:39:2:39:2 | (SSA def(x)) | x |
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| main.go:40:2:40:4 | (SSA def(ptr)) | ptr |
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| main.go:48:2:48:7 | (SSA def(result)) | result |
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| main.go:52:14:52:19 | (SSA def(result)) | result |
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| main.go:57:6:57:6 | (SSA def(x)) | x |
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| main.go:58:6:58:9 | (SSA phi(x)) | x |
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| main.go:59:3:59:3 | (SSA def(x)) | x |
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| main.go:63:2:63:2 | (SSA def(y)) | y |
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| main.go:64:6:64:6 | (SSA def(i)) | i |
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| main.go:64:16:64:18 | (SSA def(i)) | i |
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| main.go:65:6:65:9 | (SSA phi(i)) | i |
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| main.go:65:6:65:9 | (SSA phi(y)) | y |
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| main.go:68:3:68:3 | (SSA def(y)) | y |
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| main.go:73:6:73:6 | (SSA def(i)) | i |
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| main.go:73:16:73:18 | (SSA def(i)) | i |
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| main.go:74:3:74:3 | (SSA def(z)) | z |
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| main.go:74:3:74:3 | (SSA phi(i)) | i |
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| main.go:82:25:82:25 | (SSA def(b)) | b |
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| main.go:83:2:83:2 | (SSA def(x)) | x |
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| main.go:84:5:84:5 | (SSA def(a)) | a |
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| main.go:95:22:95:28 | (SSA def(wrapper)) | wrapper |
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| main.go:95:22:95:28 | (SSA def(wrapper)).s | wrapper.s |
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| main.go:96:2:96:2 | (SSA def(x)) | x |
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| main.go:97:2:99:3 | (SSA def(x)) | x |
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| main.go:98:3:98:3 | (SSA def(x)) | x |
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| main.go:103:20:103:26 | (SSA def(wrapper)) | wrapper |
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| main.go:103:20:103:26 | (SSA def(wrapper)).s | wrapper.s |
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| main.go:104:2:104:2 | (SSA def(x)) | x |
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| main.go:105:16:108:2 | (SSA def(x)) | x |
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| main.go:106:3:106:3 | (SSA def(y)) | y |
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| main.go:112:29:112:35 | (SSA def(wrapper)) | wrapper |
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| main.go:112:29:112:35 | (SSA def(wrapper)).s | wrapper.s |
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| main.go:113:2:113:2 | (SSA def(x)) | x |
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| main.go:114:2:117:3 | (SSA def(x)) | x |
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| main.go:114:16:117:2 | (SSA def(x)) | x |
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| main.go:115:3:115:3 | (SSA def(y)) | y |
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| main.go:116:3:116:3 | (SSA def(x)) | x |
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| main.go:130:3:130:3 | (SSA def(p)) | p |
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| main.go:132:3:132:3 | (SSA def(p)) | p |
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| main.go:135:2:135:2 | (SSA phi(p)) | p |
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| main.go:135:2:135:2 | (SSA phi(p)).a | p.a |
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| main.go:135:2:135:2 | (SSA phi(p)).b | p.b |
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| main.go:135:2:135:2 | (SSA phi(p)).b.a | p.b.a |
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| main.go:135:2:135:2 | (SSA phi(p)).c | p.c |

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