Rust: Block non-numeric types for number literals

Author: paldepind

rust/ql/lib/codeql/rust/frameworks/stdlib/Builtins.qll

@@ -46,72 +46,79 @@ class Str extends BuiltinType {
   Str() { this.getName() = "str" }
 }
 
+/**
+ * A numeric type.
+ *
+ * See: https://doc.rust-lang.org/reference/types/numeric.html
+ */
+abstract class NumericType extends BuiltinType { }
+
 /** The builtin `i8` type. */
-class I8 extends BuiltinType {
+class I8 extends NumericType {
   I8() { this.getName() = "i8" }
 }
 
 /** The builtin `i16` type. */
-class I16 extends BuiltinType {
+class I16 extends NumericType {
   I16() { this.getName() = "i16" }
 }
 
 /** The builtin `i32` type. */
-class I32 extends BuiltinType {
+class I32 extends NumericType {
   I32() { this.getName() = "i32" }
 }
 
 /** The builtin `i64` type. */
-class I64 extends BuiltinType {
+class I64 extends NumericType {
   I64() { this.getName() = "i64" }
 }
 
 /** The builtin `i128` type. */
-class I128 extends BuiltinType {
+class I128 extends NumericType {
   I128() { this.getName() = "i128" }
 }
 
 /** The builtin `u8` type. */
-class U8 extends BuiltinType {
+class U8 extends NumericType {
   U8() { this.getName() = "u8" }
 }
 
 /** The builtin `u16` type. */
-class U16 extends BuiltinType {
+class U16 extends NumericType {
   U16() { this.getName() = "u16" }
 }
 
 /** The builtin `u32` type. */
-class U32 extends BuiltinType {
+class U32 extends NumericType {
   U32() { this.getName() = "u32" }
 }
 
 /** The builtin `u64` type. */
-class U64 extends BuiltinType {
+class U64 extends NumericType {
   U64() { this.getName() = "u64" }
 }
 
 /** The builtin `u128` type. */
-class U128 extends BuiltinType {
+class U128 extends NumericType {
   U128() { this.getName() = "u128" }
 }
 
 /** The builtin `usize` type. */
-class Usize extends BuiltinType {
+class Usize extends NumericType {
   Usize() { this.getName() = "usize" }
 }
 
 /** The builtin `isize` type. */
-class Isize extends BuiltinType {
+class Isize extends NumericType {
   Isize() { this.getName() = "isize" }
 }
 
 /** The builtin `f32` type. */
-class F32 extends BuiltinType {
+class F32 extends NumericType {
   F32() { this.getName() = "f32" }
 }
 
 /** The builtin `f64` type. */
-class F64 extends BuiltinType {
+class F64 extends NumericType {
   F64() { this.getName() = "f64" }
 }

rust/ql/lib/codeql/rust/internal/Type.qll

@@ -146,6 +146,8 @@ class StructType extends StructOrEnumType, TStruct {
 
   StructType() { this = TStruct(struct) }
 
+  Struct asStruct() { result = struct }
+
   override ItemNode asItemNode() { result = struct }
 
   override StructField getStructField(string name) { result = struct.getStructField(name) }

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

@@ -500,10 +500,10 @@ module CertainTypeInference {
 }
 
 private Type inferLogicalOperationType(AstNode n, TypePath path) {
-  exists(Builtins::Bool t, BinaryLogicalOperation be |
+  exists(BinaryLogicalOperation be |
     n = [be, be.getLhs(), be.getRhs()] and
     path.isEmpty() and
-    result = TStruct(t)
+    result.(StructType).asStruct() instanceof Builtins::Bool
   )
 }
 
@@ -1467,6 +1467,11 @@ private Type inferLiteralType(LiteralExpr le, TypePath path, boolean certain) {
   certain = true
 }
 
+predicate uncertainNumberLiteral(LiteralExpr le) {
+  le instanceof NumberLiteralExpr and
+  not CertainTypeInference::hasInferredCertainType(le)
+}
+
 pragma[nomagic]
 private TraitType getFutureTraitType() { result.getTrait() instanceof FutureTrait }
 
@@ -2433,6 +2438,12 @@ private module Cached {
       then not CertainTypeInference::certainTypeConflict(n, path, result)
       else any()
     ) and
+    // Don't infer non-numerical types for number literals.
+    (
+      if uncertainNumberLiteral(n)
+      then result.(StructType).asStruct() instanceof Builtins::NumericType and path.isEmpty()
+      else any()
+    ) and
     (
       result = inferAssignmentOperationType(n, path)
       or