Rust: Do not infer any types for !-typed expressions

Author: hvitved

rust/ql/lib/codeql/rust/internal/typeinference/TypeInference.qll

@@ -3094,9 +3094,6 @@ private module Input3 implements InputSig3 {
     (
       n.(AssocFunctionResolution::AssocFunctionCall).resolutionDependsOnReturnType(path)
       or
-      path.isEmpty() and
-      isPanicMacroCall(n)
-      or
       n.(ArrayListExpr).getNumberOfExprs() = 0 and
       path = TypePath::singleton(getArrayTypeParameter())
     )

rust/ql/lib/codeql/rust/internal/typeinference/TypeMention.qll

@@ -678,7 +678,7 @@ private module MkTypeMention<getAdditionalPathTypeAtSig/2 getAdditionalPathTypeA
   }
 
   class NeverTypeReprMention extends TypeMentionImpl, NeverTypeRepr {
-    override Type getTypeAt(TypePath path) { result = TUnknownType() and path.isEmpty() }
+    override Type getTypeAt(TypePath path) { none() }
   }
 
   class PtrTypeReprMention extends TypeMentionImpl instanceof PtrTypeRepr {

rust/ql/test/library-tests/type-inference/type-inference.expected

@@ -8994,7 +8994,6 @@ inferType
 | main.rs:983:17:983:38 | ...::PairNone(...) |  | main.rs:972:5:978:5 | PairOption |
 | main.rs:983:17:983:38 | ...::PairNone(...) | Fst | main.rs:980:10:980:12 | Fst |
 | main.rs:983:17:983:38 | ...::PairNone(...) | Snd | main.rs:980:15:980:17 | Snd |
-| main.rs:983:43:983:82 | MacroExpr |  | main.rs:980:15:980:17 | Snd |
 | main.rs:983:50:983:81 | "PairNone has no second elemen... |  | {EXTERNAL LOCATION} | & |
 | main.rs:983:50:983:81 | "PairNone has no second elemen... | TRef | {EXTERNAL LOCATION} | str |
 | main.rs:983:50:983:81 | MacroExpr |  | {EXTERNAL LOCATION} | () |
@@ -9003,7 +9002,6 @@ inferType
 | main.rs:984:17:984:38 | ...::PairFst(...) | Fst | main.rs:980:10:980:12 | Fst |
 | main.rs:984:17:984:38 | ...::PairFst(...) | Snd | main.rs:980:15:980:17 | Snd |
 | main.rs:984:37:984:37 | _ |  | main.rs:980:10:980:12 | Fst |
-| main.rs:984:43:984:81 | MacroExpr |  | main.rs:980:15:980:17 | Snd |
 | main.rs:984:50:984:80 | "PairFst has no second element... |  | {EXTERNAL LOCATION} | & |
 | main.rs:984:50:984:80 | "PairFst has no second element... | TRef | {EXTERNAL LOCATION} | str |
 | main.rs:984:50:984:80 | MacroExpr |  | {EXTERNAL LOCATION} | () |