Rust: Type inference for macro expressions

Author: hvitved

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

@@ -265,6 +265,8 @@ private predicate typeEquality(AstNode n1, TypePath prefix1, AstNode n2, TypePat
       n1 = be.getLhs() and
       n2 = be.getRhs()
     )
+    or
+    n1 = n2.(MacroExpr).getMacroCall().getMacroCallExpansion()
   )
   or
   n1 = n2.(RefExpr).getExpr() and

rust/ql/test/library-tests/type-inference/main.rs

@@ -1812,7 +1812,7 @@ mod indexers {
 
 mod macros {
     pub fn f() {
-        let x = format!("Hello, {}", "World!"); // $ MISSING: type=x:String
+        let x = format!("Hello, {}", "World!"); // $ MISSING: type=x:String -- needs https://github.com/github/codeql/pull/19658
     }
 }
 

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

@@ -1021,8 +1021,12 @@ inferType
 | main.rs:912:19:912:22 | self | Snd | main.rs:910:15:910:17 | Snd |
 | main.rs:913:43:913:82 | MacroExpr |  | main.rs:910:15:910:17 | Snd |
 | main.rs:913:50:913:81 | "PairNone has no second elemen... |  | {EXTERNAL LOCATION} | str |
+| main.rs:913:50:913:81 | MacroExpr |  | main.rs:910:15:910:17 | Snd |
+| main.rs:913:50:913:81 | { ... } |  | main.rs:910:15:910:17 | Snd |
 | main.rs:914:43:914:81 | MacroExpr |  | main.rs:910:15:910:17 | Snd |
 | main.rs:914:50:914:80 | "PairFst has no second element... |  | {EXTERNAL LOCATION} | str |
+| main.rs:914:50:914:80 | MacroExpr |  | main.rs:910:15:910:17 | Snd |
+| main.rs:914:50:914:80 | { ... } |  | main.rs:910:15:910:17 | Snd |
 | main.rs:915:37:915:39 | snd |  | main.rs:910:15:910:17 | Snd |
 | main.rs:915:45:915:47 | snd |  | main.rs:910:15:910:17 | Snd |
 | main.rs:916:41:916:43 | snd |  | main.rs:910:15:910:17 | Snd |