Fix type alias where clause suggestion spacing issue

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -173,17 +173,19 @@ impl<'a> AstValidator<'a> {
         {
             let mut state = State::new();
 
+            let mut needs_comma = !ty_alias.after_where_clause.predicates.is_empty();
             if !ty_alias.after_where_clause.has_where_token {
                 state.space();
                 state.word_space("where");
+            } else if !needs_comma {
+                state.space();
             }
 
-            let mut first = ty_alias.after_where_clause.predicates.is_empty();
             for p in &ty_alias.generics.where_clause.predicates {
-                if !first {
+                if needs_comma {
                     state.word_space(",");
                 }
-                first = false;
+                needs_comma = true;
                 state.print_where_predicate(p);
             }
 
@@ -1832,7 +1834,11 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                     Some((right, snippet))
                 }
             };
-            let left_sp = err.span;
+            let left_sp = self
+                .sess
+                .source_map()
+                .span_extend_prev_while(err.span, char::is_whitespace)
+                .unwrap_or(err.span);
             self.lint_buffer.dyn_buffer_lint(
                 DEPRECATED_WHERE_CLAUSE_LOCATION,
                 item.id,
@@ -1846,9 +1852,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                                 sugg,
                             }
                         }
-                        None => {
-                            errors::DeprecatedWhereClauseLocationSugg::RemoveWhere { span: left_sp }
-                        }
+                        None => errors::DeprecatedWhereClauseLocationSugg::RemoveWhere {
+                            span: err.span,
+                        },
                     };
                     errors::DeprecatedWhereClauseLocation { suggestion }.into_diag(dcx, level)
                 },

tests/ui/where-clauses/alias-type-where-suggest-issue-153567.fixed

@@ -0,0 +1,17 @@
+//@ check-pass
+//@ run-rustfix
+//@ compile-flags: --force-warn deprecated_where_clause_location
+
+
+#![allow(dead_code)]
+
+trait Trait {
+    type Assoc;
+}
+
+impl Trait for i32 {
+    type Assoc = () where i32: Copy;
+    //~^ WARNING where clause not allowed here
+}
+
+fn main() {}

tests/ui/where-clauses/alias-type-where-suggest-issue-153567.rs

@@ -0,0 +1,17 @@
+//@ check-pass
+//@ run-rustfix
+//@ compile-flags: --force-warn deprecated_where_clause_location
+
+
+#![allow(dead_code)]
+
+trait Trait {
+    type Assoc;
+}
+
+impl Trait for i32 {
+    type Assoc where i32: Copy = () where;
+    //~^ WARNING where clause not allowed here
+}
+
+fn main() {}

tests/ui/where-clauses/alias-type-where-suggest-issue-153567.stderr

@@ -0,0 +1,16 @@
+warning: where clause not allowed here
+  --> $DIR/alias-type-where-suggest-issue-153567.rs:13:16
+   |
+LL |     type Assoc where i32: Copy = () where;
+   |                ^^^^^^^^^^^^^^^
+   |
+   = note: see issue #89122 <https://github.com/rust-lang/rust/issues/89122> for more information
+   = note: requested on the command line with `--force-warn deprecated-where-clause-location`
+help: move it to the end of the type declaration
+   |
+LL -     type Assoc where i32: Copy = () where;
+LL +     type Assoc = () where i32: Copy;
+   |
+
+warning: 1 warning emitted
+

tests/ui/where-clauses/where-clause-placement-assoc-type-in-impl.fixed

@@ -14,20 +14,20 @@ trait Trait {
 
 impl Trait for u32 {
     // Not fine, suggests moving.
-    type Assoc  = () where u32: Copy;
+    type Assoc = () where u32: Copy;
     //~^ WARNING where clause not allowed here
     // Not fine, suggests moving `u32: Copy`
-    type Assoc2  = () where i32: Copy, u32: Copy;
+    type Assoc2 = () where i32: Copy, u32: Copy;
     //~^ WARNING where clause not allowed here
-    type Assoc3  = () where;
+    type Assoc3 = () where;
     //~^ WARNING where clause not allowed here
 }
 
 impl Trait for i32 {
     // Fine.
     type Assoc = () where u32: Copy;
     // Not fine, suggests moving both.
-    type Assoc2  = () where u32: Copy, i32: Copy;
+    type Assoc2 = () where u32: Copy, i32: Copy;
     //~^ WARNING where clause not allowed here
     type Assoc3  = () where;
     //~^ WARNING where clause not allowed here

tests/ui/where-clauses/where-clause-placement-assoc-type-in-impl.stderr

@@ -9,7 +9,7 @@ LL |     type Assoc where u32: Copy = ();
 help: move it to the end of the type declaration
    |
 LL -     type Assoc where u32: Copy = ();
-LL +     type Assoc  = () where u32: Copy;
+LL +     type Assoc = () where u32: Copy;
    |
 
 warning: where clause not allowed here
@@ -22,7 +22,7 @@ LL |     type Assoc2 where u32: Copy = () where i32: Copy;
 help: move it to the end of the type declaration
    |
 LL -     type Assoc2 where u32: Copy = () where i32: Copy;
-LL +     type Assoc2  = () where i32: Copy, u32: Copy;
+LL +     type Assoc2 = () where i32: Copy, u32: Copy;
    |
 
 warning: where clause not allowed here
@@ -35,7 +35,7 @@ LL |     type Assoc3 where = ();
 help: move it to the end of the type declaration
    |
 LL -     type Assoc3 where = ();
-LL +     type Assoc3  = () where;
+LL +     type Assoc3 = () where;
    |
 
 warning: where clause not allowed here
@@ -48,7 +48,7 @@ LL |     type Assoc2 where u32: Copy, i32: Copy = ();
 help: move it to the end of the type declaration
    |
 LL -     type Assoc2 where u32: Copy, i32: Copy = ();
-LL +     type Assoc2  = () where u32: Copy, i32: Copy;
+LL +     type Assoc2 = () where u32: Copy, i32: Copy;
    |
 
 warning: where clause not allowed here

tests/ui/where-clauses/where-clause-placement-assoc-type-in-trait.fixed

@@ -6,10 +6,10 @@
 
 trait Trait {
     // Not fine, suggests moving.
-    type Assoc  = () where u32: Copy;
+    type Assoc = () where u32: Copy;
     //~^ WARNING where clause not allowed here
     // Not fine, suggests moving `u32: Copy`
-    type Assoc2  = () where i32: Copy, u32: Copy;
+    type Assoc2 = () where i32: Copy, u32: Copy;
     //~^ WARNING where clause not allowed here
 }
 

tests/ui/where-clauses/where-clause-placement-assoc-type-in-trait.stderr

@@ -9,7 +9,7 @@ LL |     type Assoc where u32: Copy = ();
 help: move it to the end of the type declaration
    |
 LL -     type Assoc where u32: Copy = ();
-LL +     type Assoc  = () where u32: Copy;
+LL +     type Assoc = () where u32: Copy;
    |
 
 warning: where clause not allowed here
@@ -22,7 +22,7 @@ LL |     type Assoc2 where u32: Copy = () where i32: Copy;
 help: move it to the end of the type declaration
    |
 LL -     type Assoc2 where u32: Copy = () where i32: Copy;
-LL +     type Assoc2  = () where i32: Copy, u32: Copy;
+LL +     type Assoc2 = () where i32: Copy, u32: Copy;
    |
 
 warning: 2 warnings emitted