Check for unused results in a few more places

It appears I pushed my changes a little too soon and forgot about a few
additional cases where we need to check and warn about unused call
results.

Author: yorickpeterse

compiler/src/hir.rs

@@ -144,6 +144,7 @@ pub(crate) struct ConstantRef {
     pub(crate) source: Option<Identifier>,
     pub(crate) name: String,
     pub(crate) resolved_type: types::TypeRef,
+    pub(crate) unused: bool,
     pub(crate) location: Location,
 }
 
@@ -228,6 +229,7 @@ pub(crate) struct AssignSetter {
     pub(crate) name: Identifier,
     pub(crate) value: Expression,
     pub(crate) location: Location,
+    pub(crate) unused: bool,
     pub(crate) expected_type: types::TypeRef,
 }
 
@@ -2206,6 +2208,7 @@ impl<'a> LowerToHir<'a> {
                         source: None,
                         name: ARRAY_INTERNAL_NAME.to_string(),
                         resolved_type: types::TypeRef::Unknown,
+                        unused: false,
                         location: node.location,
                     },
                 ))),
@@ -2327,6 +2330,8 @@ impl<'a> LowerToHir<'a> {
             match node {
                 Expression::Call(c) => c.unused = rem,
                 Expression::IdentifierRef(c) => c.unused = rem,
+                Expression::ConstantRef(c) => c.unused = rem,
+                Expression::AssignSetter(c) => c.unused = rem,
                 _ => {}
             }
         }
@@ -2516,6 +2521,7 @@ impl<'a> LowerToHir<'a> {
             source: self.optional_identifier(node.source),
             name: node.name,
             resolved_type: types::TypeRef::Unknown,
+            unused: false,
             location: node.location,
         })
     }
@@ -2795,6 +2801,7 @@ impl<'a> LowerToHir<'a> {
             name: self.identifier(node.name),
             value: self.expression(node.value),
             location: node.location,
+            unused: false,
             expected_type: types::TypeRef::Unknown,
         })
     }
@@ -2856,6 +2863,7 @@ impl<'a> LowerToHir<'a> {
                 location: node.location,
             })),
             location: node.location,
+            unused: false,
             expected_type: types::TypeRef::Unknown,
         })
     }
@@ -5620,6 +5628,7 @@ mod tests {
                                     source: None,
                                     name: "$Array".to_string(),
                                     resolved_type: types::TypeRef::Unknown,
+                                    unused: false,
                                     location: cols(8, 11),
                                 }
                             ))),
@@ -5721,6 +5730,7 @@ mod tests {
                                     source: None,
                                     name: "$Array".to_string(),
                                     resolved_type: types::TypeRef::Unknown,
+                                    unused: false,
                                     location: loc(2, 4, 15, 15),
                                 }
                             ))),
@@ -5869,6 +5879,7 @@ mod tests {
                 source: None,
                 name: "A".to_string(),
                 resolved_type: types::TypeRef::Unknown,
+                unused: false,
                 location: cols(8, 8)
             }))
         );
@@ -6231,6 +6242,7 @@ mod tests {
                     location: cols(14, 14)
                 })),
                 location: cols(8, 14),
+                unused: false,
                 expected_type: types::TypeRef::Unknown,
             }))
         );
@@ -6296,6 +6308,7 @@ mod tests {
                     location: cols(8, 15)
                 })),
                 location: cols(8, 15),
+                unused: false,
                 expected_type: types::TypeRef::Unknown,
             }))
         );

compiler/src/type_check/expressions.rs

@@ -2559,6 +2559,10 @@ impl<'a> CheckMethodBody<'a> {
             type_arguments: call.type_arguments,
         });
 
+        if node.unused && returns.must_use(self.db(), rec) {
+            self.state.diagnostics.unused_result(self.file(), node.location);
+        }
+
         node.resolved_type = returns;
         node.resolved_type
     }
@@ -3299,6 +3303,10 @@ impl<'a> CheckMethodBody<'a> {
             type_arguments: call.type_arguments,
         });
 
+        if node.unused && returns.must_use(self.db(), receiver) {
+            self.state.diagnostics.unused_result(self.file(), node.location);
+        }
+
         returns
     }
 

std/fixtures/diagnostics/unused_results.inko

@@ -1,5 +1,13 @@
 let ARRAY = [10]
 
+type User {
+  let mut @name: String
+
+  fn mut name=(name: String) -> String {
+    @name := name
+  }
+}
+
 fn return_bool -> Bool {
   true
 }
@@ -36,6 +44,10 @@ fn return_never -> Never {
   panic('oops')
 }
 
+fn Constant_method -> Int {
+  42
+}
+
 fn example1 {
   return_bool
   return_nil
@@ -46,6 +58,7 @@ fn example1 {
   return_borrow
   return_option
   Option.Some(10).as_ref
+  Constant_method
   nil
 }
 
@@ -59,6 +72,7 @@ fn example2 {
   return_borrow()
   return_option()
   Option.Some(10).as_ref()
+  Constant_method()
   nil
 }
 
@@ -71,14 +85,28 @@ fn example4 {
   nil
 }
 
-# unused_results.inko:42:3 warning(unused-result): the result of this expression is unused
-# unused_results.inko:43:3 warning(unused-result): the result of this expression is unused
-# unused_results.inko:44:3 warning(unused-result): the result of this expression is unused
-# unused_results.inko:45:3 warning(unused-result): the result of this expression is unused
-# unused_results.inko:48:3 warning(unused-result): the result of this expression is unused
+fn example5 {
+  10 + 5
+  nil
+}
+
+fn example6(value: User) {
+  value.name = 'Alice'
+  nil
+}
+
+# unused_results.inko:54:3 warning(unused-result): the result of this expression is unused
 # unused_results.inko:55:3 warning(unused-result): the result of this expression is unused
 # unused_results.inko:56:3 warning(unused-result): the result of this expression is unused
 # unused_results.inko:57:3 warning(unused-result): the result of this expression is unused
-# unused_results.inko:58:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:60:3 warning(unused-result): the result of this expression is unused
 # unused_results.inko:61:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:68:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:69:3 warning(unused-result): the result of this expression is unused
 # unused_results.inko:70:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:71:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:74:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:75:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:84:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:89:3 warning(unused-result): the result of this expression is unused
+# unused_results.inko:94:3 warning(unused-result): the result of this expression is unused

std/test/std/test_env.inko

@@ -67,8 +67,8 @@ fn pub tests(t: mut Tests) {
     'env.working_directory=',
     child: fn {
       let out = Stdout.new
+      let _ = env.working_directory = env.temporary_directory
 
-      env.working_directory = env.temporary_directory
       out.write_string(env.working_directory.get.to_string)
     },
     test: fn (test, process) {