gccrs: respect the unify rules commit flag

philberty · philberty · commit 567b4040355c · 2025-08-31T16:34:43.000Z
We use the types compatable interface for unify here and so if
we dont respect the commit flag the interface can have unintended
side effects with infer type hints throwing things off down the line.

gcc/rust/ChangeLog:

	* typecheck/rust-unify.cc (UnifyRules::expect_inference_variable): dont commit
	(UnifyRules::expect_adt): likewise
	(UnifyRules::expect_bool): likewise
	(UnifyRules::expect_char): likewise
	(UnifyRules::expect_int): likewise
	(UnifyRules::expect_uint): likewise
	(UnifyRules::expect_float): likewise
	(UnifyRules::expect_isize): likewise
	(UnifyRules::expect_usize): likewise

Signed-off-by: Philip Herron &lt;herron.philip@googlemail.com&gt;
diff --git a/gcc/rust/typecheck/rust-unify.cc b/gcc/rust/typecheck/rust-unify.cc
@@ -385,7 +385,8 @@ UnifyRules::expect_inference_variable (TyTy::InferType *ltype,
 			    == TyTy::InferType::InferTypeKind::INTEGRAL);
 	if (is_valid)
 	  {
-	    ltype->apply_primitive_type_hint (*rtype);
+	    if (commit_flag)
+	      ltype->apply_primitive_type_hint (*rtype);
 	    return rtype;
 	  }
       }
@@ -399,7 +400,8 @@ UnifyRules::expect_inference_variable (TyTy::InferType *ltype,
 			    == TyTy::InferType::InferTypeKind::FLOAT);
 	if (is_valid)
 	  {
-	    ltype->apply_primitive_type_hint (*rtype);
+	    if (commit_flag)
+	      ltype->apply_primitive_type_hint (*rtype);
 	    return rtype;
 	  }
       }
@@ -523,7 +525,7 @@ UnifyRules::expect_adt (TyTy::ADTType *ltype, TyTy::BaseType *rtype)
 	      }
 	  }
 
-	return type.clone ();
+	return ltype;
       }
       break;
 
@@ -1269,7 +1271,8 @@ UnifyRules::expect_bool (TyTy::BoolType *ltype, TyTy::BaseType *rtype)
 	  = r->get_infer_kind () == TyTy::InferType::InferTypeKind::GENERAL;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }
@@ -1319,7 +1322,8 @@ UnifyRules::expect_char (TyTy::CharType *ltype, TyTy::BaseType *rtype)
 	  = r->get_infer_kind () == TyTy::InferType::InferTypeKind::GENERAL;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }
@@ -1370,7 +1374,8 @@ UnifyRules::expect_int (TyTy::IntType *ltype, TyTy::BaseType *rtype)
 	    || r->get_infer_kind () == TyTy::InferType::InferTypeKind::INTEGRAL;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }
@@ -1428,7 +1433,8 @@ UnifyRules::expect_uint (TyTy::UintType *ltype, TyTy::BaseType *rtype)
 	    || r->get_infer_kind () == TyTy::InferType::InferTypeKind::INTEGRAL;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }
@@ -1486,7 +1492,8 @@ UnifyRules::expect_float (TyTy::FloatType *ltype, TyTy::BaseType *rtype)
 	    || r->get_infer_kind () == TyTy::InferType::InferTypeKind::FLOAT;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }
@@ -1543,7 +1550,8 @@ UnifyRules::expect_isize (TyTy::ISizeType *ltype, TyTy::BaseType *rtype)
 	  = r->get_infer_kind () != TyTy::InferType::InferTypeKind::FLOAT;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }
@@ -1593,7 +1601,8 @@ UnifyRules::expect_usize (TyTy::USizeType *ltype, TyTy::BaseType *rtype)
 	  = r->get_infer_kind () != TyTy::InferType::InferTypeKind::FLOAT;
 	if (is_valid)
 	  {
-	    r->apply_primitive_type_hint (*ltype);
+	    if (commit_flag)
+	      r->apply_primitive_type_hint (*ltype);
 	    return ltype->clone ();
 	  }
       }

Original file line number	Diff line number	Diff line change
`@@ -385,7 +385,8 @@ UnifyRules::expect_inference_variable (TyTy::InferType *ltype,`
`385`	`385`	`== TyTy::InferType::InferTypeKind::INTEGRAL);`
`386`	`386`	`if (is_valid)`
`387`	`387`	`{`
`388`		`- ltype->apply_primitive_type_hint (*rtype);`
	`388`	`+ if (commit_flag)`
	`389`	`+ ltype->apply_primitive_type_hint (*rtype);`
`389`	`390`	`return rtype;`
`390`	`391`	`}`
`391`	`392`	`}`
`@@ -399,7 +400,8 @@ UnifyRules::expect_inference_variable (TyTy::InferType *ltype,`
`399`	`400`	`== TyTy::InferType::InferTypeKind::FLOAT);`
`400`	`401`	`if (is_valid)`
`401`	`402`	`{`
`402`		`- ltype->apply_primitive_type_hint (*rtype);`
	`403`	`+ if (commit_flag)`
	`404`	`+ ltype->apply_primitive_type_hint (*rtype);`
`403`	`405`	`return rtype;`
`404`	`406`	`}`
`405`	`407`	`}`
`@@ -523,7 +525,7 @@ UnifyRules::expect_adt (TyTy::ADTType ltype, TyTy::BaseType rtype)`
`523`	`525`	`}`
`524`	`526`	`}`
`525`	`527`
`526`		`- return type.clone ();`
	`528`	`+ return ltype;`
`527`	`529`	`}`
`528`	`530`	`break;`
`529`	`531`
`@@ -1269,7 +1271,8 @@ UnifyRules::expect_bool (TyTy::BoolType ltype, TyTy::BaseType rtype)`
`1269`	`1271`	`= r->get_infer_kind () == TyTy::InferType::InferTypeKind::GENERAL;`
`1270`	`1272`	`if (is_valid)`
`1271`	`1273`	`{`
`1272`		`- r->apply_primitive_type_hint (*ltype);`
	`1274`	`+ if (commit_flag)`
	`1275`	`+ r->apply_primitive_type_hint (*ltype);`
`1273`	`1276`	`return ltype->clone ();`
`1274`	`1277`	`}`
`1275`	`1278`	`}`
`@@ -1319,7 +1322,8 @@ UnifyRules::expect_char (TyTy::CharType ltype, TyTy::BaseType rtype)`
`1319`	`1322`	`= r->get_infer_kind () == TyTy::InferType::InferTypeKind::GENERAL;`
`1320`	`1323`	`if (is_valid)`
`1321`	`1324`	`{`
`1322`		`- r->apply_primitive_type_hint (*ltype);`
	`1325`	`+ if (commit_flag)`
	`1326`	`+ r->apply_primitive_type_hint (*ltype);`
`1323`	`1327`	`return ltype->clone ();`
`1324`	`1328`	`}`
`1325`	`1329`	`}`
`@@ -1370,7 +1374,8 @@ UnifyRules::expect_int (TyTy::IntType ltype, TyTy::BaseType rtype)`
`1370`	`1374`	`\|\| r->get_infer_kind () == TyTy::InferType::InferTypeKind::INTEGRAL;`
`1371`	`1375`	`if (is_valid)`
`1372`	`1376`	`{`
`1373`		`- r->apply_primitive_type_hint (*ltype);`
	`1377`	`+ if (commit_flag)`
	`1378`	`+ r->apply_primitive_type_hint (*ltype);`
`1374`	`1379`	`return ltype->clone ();`
`1375`	`1380`	`}`
`1376`	`1381`	`}`
`@@ -1428,7 +1433,8 @@ UnifyRules::expect_uint (TyTy::UintType ltype, TyTy::BaseType rtype)`
`1428`	`1433`	`\|\| r->get_infer_kind () == TyTy::InferType::InferTypeKind::INTEGRAL;`
`1429`	`1434`	`if (is_valid)`
`1430`	`1435`	`{`
`1431`		`- r->apply_primitive_type_hint (*ltype);`
	`1436`	`+ if (commit_flag)`
	`1437`	`+ r->apply_primitive_type_hint (*ltype);`
`1432`	`1438`	`return ltype->clone ();`
`1433`	`1439`	`}`
`1434`	`1440`	`}`
`@@ -1486,7 +1492,8 @@ UnifyRules::expect_float (TyTy::FloatType ltype, TyTy::BaseType rtype)`
`1486`	`1492`	`\|\| r->get_infer_kind () == TyTy::InferType::InferTypeKind::FLOAT;`
`1487`	`1493`	`if (is_valid)`
`1488`	`1494`	`{`
`1489`		`- r->apply_primitive_type_hint (*ltype);`
	`1495`	`+ if (commit_flag)`
	`1496`	`+ r->apply_primitive_type_hint (*ltype);`
`1490`	`1497`	`return ltype->clone ();`
`1491`	`1498`	`}`
`1492`	`1499`	`}`
`@@ -1543,7 +1550,8 @@ UnifyRules::expect_isize (TyTy::ISizeType ltype, TyTy::BaseType rtype)`
`1543`	`1550`	`= r->get_infer_kind () != TyTy::InferType::InferTypeKind::FLOAT;`
`1544`	`1551`	`if (is_valid)`
`1545`	`1552`	`{`
`1546`		`- r->apply_primitive_type_hint (*ltype);`
	`1553`	`+ if (commit_flag)`
	`1554`	`+ r->apply_primitive_type_hint (*ltype);`
`1547`	`1555`	`return ltype->clone ();`
`1548`	`1556`	`}`
`1549`	`1557`	`}`
`@@ -1593,7 +1601,8 @@ UnifyRules::expect_usize (TyTy::USizeType ltype, TyTy::BaseType rtype)`
`1593`	`1601`	`= r->get_infer_kind () != TyTy::InferType::InferTypeKind::FLOAT;`
`1594`	`1602`	`if (is_valid)`
`1595`	`1603`	`{`
`1596`		`- r->apply_primitive_type_hint (*ltype);`
	`1604`	`+ if (commit_flag)`
	`1605`	`+ r->apply_primitive_type_hint (*ltype);`
`1597`	`1606`	`return ltype->clone ();`
`1598`	`1607`	`}`
`1599`	`1608`	`}`