Kotlin: include !! operands in qualified-call locations under K1

For a call qualified through a not-null assertion (e.g. `s!!.foo()`),
`TrapWriter.getStartOffset` derives the call's start from its receiver.
Under K1 the receiver is the `CHECK_NOT_NULL`/EXCLEXCL intrinsic IrCall,
whose own `startOffset` points at the first `!` character rather than at
the operand `s`. The enclosing call therefore inherited the `!!` offset
and omitted the receiver operand from its span.

The `!!` intrinsic carries its operand as value argument 0 (not as a
dispatch/extension receiver), so the existing receiver-based adjustment
did not reach it. Extend `getStartOffset` to also consider value
argument 0 of an EXCLEXCL call, recursively. This makes a `!!`-qualified
call span from the operand, matching K2, which already anchors the
receiver at the operand.

The change affects source locations only; AST structure, call targets,
and dataflow relationships are unchanged. K2 output is unaffected because
its offsets already start at the operand. Fully converges
dataflow/notnullexpr and exprs/binop between the K1 and K2 suites and
removes 6 divergent rows overall.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 86bfc022-3ecc-4746-ba23-3b76c4e4c3e4

java/kotlin-extractor/src/main/kotlin/TrapWriter.kt

@@ -2,6 +2,7 @@ package com.github.codeql
 
 import com.github.codeql.KotlinUsesExtractor.LocallyVisibleFunctionLabels
 import com.github.codeql.utils.versions.codeQlExtensionReceiver
+import com.github.codeql.utils.versions.codeQlGetValueArgument
 import com.semmle.extractor.java.PopulateFile
 import com.semmle.util.unicode.UTF8Util
 import java.io.BufferedWriter
@@ -14,6 +15,7 @@ import org.jetbrains.kotlin.ir.declarations.IrFunction
 import org.jetbrains.kotlin.ir.declarations.IrVariable
 import org.jetbrains.kotlin.ir.declarations.path
 import org.jetbrains.kotlin.ir.expressions.IrCall
+import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
 import org.jetbrains.kotlin.ir.util.SYNTHETIC_OFFSET
 
 /**
@@ -347,7 +349,17 @@ open class FileTrapWriter(
                 // Calls have incorrect startOffset, so we adjust them:
                 val dr = e.dispatchReceiver?.let { getStartOffset(it) }
                 val er = e.codeQlExtensionReceiver?.let { getStartOffset(it) }
-                offsetMinOf(e.startOffset, dr, er)
+                // The `!!` (CHECK_NOT_NULL / EXCLEXCL) intrinsic carries its operand as value
+                // argument 0 rather than as a dispatch/extension receiver, and in K1 its own
+                // startOffset points at the `!` token rather than the operand. Consider the
+                // operand's start so that a call qualified through a `!!` expression (e.g.
+                // `s!!.foo()`) spans from the operand. K2 already starts at the operand, so it is
+                // unaffected.
+                val exclOperand =
+                    if (e.origin == IrStatementOrigin.EXCLEXCL)
+                        e.codeQlGetValueArgument(0)?.let { getStartOffset(it) }
+                    else null
+                offsetMinOf(e.startOffset, dr, er, exclOperand)
             }
             else -> e.startOffset
         }

java/ql/test-kotlin1/library-tests/dataflow/notnullexpr/test.expected

@@ -1 +1 @@
-| NotNullExpr.kt:7:14:7:20 | taint(...) | NotNullExpr.kt:8:12:8:33 | getQueryParameter(...) |
+| NotNullExpr.kt:7:14:7:20 | taint(...) | NotNullExpr.kt:8:10:8:33 | getQueryParameter(...) |

java/ql/test-kotlin1/library-tests/exprs/binop.expected

@@ -96,7 +96,7 @@
 | exprs.kt:141:12:141:20 | ... + ... | exprs.kt:141:12:141:14 | 123 | exprs.kt:141:18:141:20 | 456 |
 | exprs.kt:167:8:167:16 | ... (value not-equals) ... | exprs.kt:167:8:167:8 | r | exprs.kt:167:13:167:16 | null |
 | exprs.kt:196:31:196:37 | ... + ... | exprs.kt:196:31:196:32 | getA1(...) | exprs.kt:196:36:196:37 | a2 |
-| exprs.kt:211:20:211:29 | ... + ... | exprs.kt:211:19:211:21 | ...!! | exprs.kt:211:28:211:28 | 5 |
+| exprs.kt:211:19:211:29 | ... + ... | exprs.kt:211:19:211:21 | ...!! | exprs.kt:211:28:211:28 | 5 |
 | exprs.kt:212:19:212:25 | ... + ... | exprs.kt:212:19:212:21 | ...!! | exprs.kt:212:25:212:25 | 5 |
 | exprs.kt:230:12:230:47 | ... (value equals) ... | exprs.kt:230:12:230:27 | notNullPrimitive | exprs.kt:230:32:230:47 | notNullPrimitive |
 | exprs.kt:231:12:231:48 | ... (value equals) ... | exprs.kt:231:12:231:27 | notNullPrimitive | exprs.kt:231:32:231:48 | nullablePrimitive |

java/ql/test-kotlin1/library-tests/exprs/exprs.expected

@@ -1593,7 +1593,7 @@
 | exprs.kt:211:9:211:29 | b2 | exprs.kt:206:5:217:5 | x | LocalVariableDeclExpr |
 | exprs.kt:211:19:211:19 | s | exprs.kt:206:5:217:5 | x | VarAccess |
 | exprs.kt:211:19:211:21 | ...!! | exprs.kt:206:5:217:5 | x | NotNullExpr |
-| exprs.kt:211:20:211:29 | ... + ... | exprs.kt:206:5:217:5 | x | AddExpr |
+| exprs.kt:211:19:211:29 | ... + ... | exprs.kt:206:5:217:5 | x | AddExpr |
 | exprs.kt:211:28:211:28 | 5 | exprs.kt:206:5:217:5 | x | IntegerLiteral |
 | exprs.kt:212:9:212:25 | b3 | exprs.kt:206:5:217:5 | x | LocalVariableDeclExpr |
 | exprs.kt:212:19:212:19 | s | exprs.kt:206:5:217:5 | x | VarAccess |