Guards: remove boolean outcome block hook

Keep support for compound guards represented by CFG after-value nodes out of the Go shared-guards migration. This behavior can be reconsidered as part of a broader Guards/CFG integration.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: owen-mc

go/ql/lib/semmle/go/controlflow/Guards.qll

@@ -26,16 +26,6 @@ private module GuardsInput implements
 
   class Expr = G::Expr;
 
-  predicate booleanOutcomeBlock(Expr guard, CfgImpl::Cfg::BasicBlock outcomeBlock, boolean branch) {
-    exists(CfgImpl::Cfg::ControlFlowNode outcomeNode |
-      branch = true and outcomeNode.isAfterTrue(guard)
-      or
-      branch = false and outcomeNode.isAfterFalse(guard)
-    |
-      outcomeBlock = outcomeNode.getBasicBlock()
-    )
-  }
-
   private newtype TConstantValue = TStringValue(string s) { s = any(G::Expr e).getStringValue() }
 
   class ConstantValue extends TConstantValue {

go/ql/test/library-tests/semmle/go/controlflow/Guards/Guards.expected

@@ -15,9 +15,6 @@ controlsResult
 | guards.go:42:2:43:33 | case clause | tagged false comparison | true |
 | guards.go:42:7:42:17 | ...<... | tagged false comparison | false |
 | guards.go:48:5:48:5 | a | compound true | true |
-| guards.go:48:5:48:17 | ...&&... | compound false | false |
-| guards.go:48:5:48:17 | ...&&... | compound true | true |
-| guards.go:48:11:48:16 | ...\|\|... | compound true | true |
 | guards.go:56:5:56:20 | ...==... | upcast | true |
 | guards.go:59:5:59:19 | ...==... | downcast | true |
 | guards.go:62:5:62:22 | ...==... | upcast narrow | true |
@@ -86,9 +83,6 @@ valueControlsResult
 | guards.go:42:7:42:12 | number | tagged false comparison | Lower bound 10 |
 | guards.go:42:7:42:17 | ...<... | tagged false comparison | false |
 | guards.go:48:5:48:5 | a | compound true | true |
-| guards.go:48:5:48:17 | ...&&... | compound false | false |
-| guards.go:48:5:48:17 | ...&&... | compound true | true |
-| guards.go:48:11:48:16 | ...\|\|... | compound true | true |
 | guards.go:56:5:56:15 | type conversion | upcast | 0 |
 | guards.go:56:5:56:20 | ...==... | upcast | true |
 | guards.go:56:11:56:14 | wide | upcast | 0 |

shared/controlflow/codeql/controlflow/Guards.qll

@@ -78,14 +78,6 @@ signature module InputSig<LocationSig Location, TypSig ControlFlowNode, TypSig B
     BasicBlock getBasicBlock();
   }
 
-  /**
-   * Holds if `outcomeBlock` contains a control flow node indicating that
-   * `guard` evaluated to `branch`.
-   */
-  default predicate booleanOutcomeBlock(Expr guard, BasicBlock outcomeBlock, boolean branch) {
-    none()
-  }
-
   class ConstantValue {
     /** Gets a textual representation of this constant value. */
     string toString();
@@ -1540,11 +1532,6 @@ module Make<
           dominatingEdge(guard, succ) and
           succ.dominates(bb)
         )
-        or
-        exists(BasicBlock outcomeBlock |
-          booleanOutcomeBlock(this, outcomeBlock, v.asBooleanValue()) and
-          outcomeBlock.dominates(bb)
-        )
       }
 
       /**