[flake8-return] Fix indentation syntax error (RET505) (#9705)

## Summary

Fix for
https://github.com/astral-sh/ruff/issues/8402#issuecomment-1916223126

## Test Plan

`cargo test`

crates/ruff_linter/resources/test/fixtures/flake8_return/RET505.py

@@ -103,6 +103,14 @@ def bar4(x):
             return None
 
 
+def fibo(n):
+    if n<2:
+        return n;
+    else:
+        last = 1;
+        last2 = 0;
+
+
 ###
 # Non-error
 ###

crates/ruff_linter/src/rules/flake8_return/rules/function.rs

@@ -820,15 +820,14 @@ fn remove_else(
 
         // If the statement is on the same line as the `else`, just remove the `else: `.
         // Ex) `else: return True` -> `return True`
-        let Some(first) = elif_else.body.first() else {
+        if let [first] = elif_else.body.as_slice() {
-            return Err(anyhow::anyhow!("`else` statement has no body"));
-        };
             if indexer.in_multi_statement_line(first, locator) {
                 return Ok(Fix::safe_edit(Edit::deletion(
                     elif_else.start(),
                     first.start(),
                 )));
             }
+        }
 
         // we're deleting the `else`, and it's Colon, and the rest of the line(s) they're on,
         // so here we get the last position of the line the Colon is on

crates/ruff_linter/src/rules/flake8_return/snapshots/ruff_linter__rules__flake8_return__tests__RET505_RET505.py.snap

@@ -89,14 +89,14 @@ RET505.py:99:5: RET505 Unnecessary `else` after `return` statement
     |
     = help: Remove unnecessary `else`
 
-RET505.py:137:5: RET505 Unnecessary `else` after `return` statement
+RET505.py:109:5: RET505 Unnecessary `else` after `return` statement
     |
-135 |     if True:
+107 |     if n<2:
-136 |         return
+108 |         return n;
-137 |     else:
+109 |     else:
     |     ^^^^ RET505
-138 |         # comment
+110 |         last = 1;
-139 |         pass
+111 |         last2 = 0;
     |
     = help: Remove unnecessary `else`
 
@@ -104,31 +104,31 @@ RET505.py:145:5: RET505 Unnecessary `else` after `return` statement
     |
 143 |     if True:
 144 |         return
-145 |     else:  # comment
+145 |     else:
     |     ^^^^ RET505
-146 |         pass
+146 |         # comment
+147 |         pass
     |
     = help: Remove unnecessary `else`
 
-RET505.py:152:5: RET505 Unnecessary `else` after `return` statement
+RET505.py:153:5: RET505 Unnecessary `else` after `return` statement
     |
-150 |     if True:
+151 |     if True:
-151 |         return
+152 |         return
-152 |     else\
+153 |     else:  # comment
     |     ^^^^ RET505
-153 |         :\
+154 |         pass
-154 |         # comment
     |
     = help: Remove unnecessary `else`
 
-RET505.py:161:5: RET505 Unnecessary `else` after `return` statement
+RET505.py:160:5: RET505 Unnecessary `else` after `return` statement
     |
-159 |     if True:
+158 |     if True:
-160 |         return
+159 |         return
-161 |     else\
+160 |     else\
     |     ^^^^ RET505
-162 |         :  # comment
+161 |         :\
-163 |         pass
+162 |         # comment
     |
     = help: Remove unnecessary `else`
 
@@ -136,18 +136,29 @@ RET505.py:169:5: RET505 Unnecessary `else` after `return` statement
     |
 167 |     if True:
 168 |         return
-169 |     else: pass
+169 |     else\
+    |     ^^^^ RET505
+170 |         :  # comment
+171 |         pass
+    |
+    = help: Remove unnecessary `else`
+
+RET505.py:177:5: RET505 Unnecessary `else` after `return` statement
+    |
+175 |     if True:
+176 |         return
+177 |     else: pass
     |     ^^^^ RET505
     |
     = help: Remove unnecessary `else`
 
-RET505.py:175:5: RET505 Unnecessary `else` after `return` statement
+RET505.py:183:5: RET505 Unnecessary `else` after `return` statement
     |
-173 |     if True:
+181 |     if True:
-174 |         return
+182 |         return
-175 |     else:\
+183 |     else:\
     |     ^^^^ RET505
-176 |         pass
+184 |         pass
     |
     = help: Remove unnecessary `else`
 

crates/ruff_linter/src/rules/flake8_return/snapshots/ruff_linter__rules__flake8_return__tests__preview__RET505_RET505.py.snap

@@ -182,141 +182,165 @@ RET505.py:99:5: RET505 [*] Unnecessary `else` after `return` statement
     102 |+        return None
 104 103 | 
 105 104 | 
-106 105 | ###
+106 105 | def fibo(n):
 
-RET505.py:137:5: RET505 [*] Unnecessary `else` after `return` statement
+RET505.py:109:5: RET505 [*] Unnecessary `else` after `return` statement
     |
-135 |     if True:
+107 |     if n<2:
-136 |         return
+108 |         return n;
-137 |     else:
+109 |     else:
     |     ^^^^ RET505
-138 |         # comment
+110 |         last = 1;
-139 |         pass
+111 |         last2 = 0;
     |
     = help: Remove unnecessary `else`
 
 ℹ Safe fix
-134 134 | def bar4(x):
+106 106 | def fibo(n):
-135 135 |     if True:
+107 107 |     if n<2:
-136 136 |         return
+108 108 |         return n;
-137     |-    else:
+109     |-    else:
-138     |-        # comment
+110     |-        last = 1;
-139     |-        pass
+111     |-        last2 = 0;
-    137 |+    # comment
+    109 |+    last = 1;
-    138 |+    pass
+    110 |+    last2 = 0;
-140 139 | 
+112 111 | 
-141 140 | 
+113 112 | 
-142 141 | def bar5():
+114 113 | ###
 
 RET505.py:145:5: RET505 [*] Unnecessary `else` after `return` statement
     |
 143 |     if True:
 144 |         return
-145 |     else:  # comment
+145 |     else:
     |     ^^^^ RET505
-146 |         pass
+146 |         # comment
+147 |         pass
     |
     = help: Remove unnecessary `else`
 
 ℹ Safe fix
-142 142 | def bar5():
+142 142 | def bar4(x):
 143 143 |     if True:
 144 144 |         return
-145     |-    else:  # comment
+145     |-    else:
-146     |-        pass
+146     |-        # comment
+147     |-        pass
     145 |+    # comment
     146 |+    pass
-147 147 | 
+148 147 | 
-148 148 | 
+149 148 | 
-149 149 | def bar6():
+150 149 | def bar5():
 
-RET505.py:152:5: RET505 [*] Unnecessary `else` after `return` statement
+RET505.py:153:5: RET505 [*] Unnecessary `else` after `return` statement
     |
-150 |     if True:
+151 |     if True:
-151 |         return
+152 |         return
-152 |     else\
+153 |     else:  # comment
     |     ^^^^ RET505
-153 |         :\
+154 |         pass
-154 |         # comment
     |
     = help: Remove unnecessary `else`
 
 ℹ Safe fix
-149 149 | def bar6():
+150 150 | def bar5():
-150 150 |     if True:
+151 151 |     if True:
-151 151 |         return
+152 152 |         return
-152     |-    else\
+153     |-    else:  # comment
-153     |-        :\
+154     |-        pass
-154     |-        # comment
+    153 |+    # comment
-155     |-        pass
+    154 |+    pass
-    152 |+    # comment
+155 155 | 
-    153 |+    pass
+156 156 | 
-156 154 | 
+157 157 | def bar6():
-157 155 | 
-158 156 | def bar7():
 
-RET505.py:161:5: RET505 [*] Unnecessary `else` after `return` statement
+RET505.py:160:5: RET505 [*] Unnecessary `else` after `return` statement
     |
-159 |     if True:
+158 |     if True:
-160 |         return
+159 |         return
-161 |     else\
+160 |     else\
     |     ^^^^ RET505
-162 |         :  # comment
+161 |         :\
-163 |         pass
+162 |         # comment
     |
     = help: Remove unnecessary `else`
 
 ℹ Safe fix
-158 158 | def bar7():
+157 157 | def bar6():
-159 159 |     if True:
+158 158 |     if True:
-160 160 |         return
+159 159 |         return
-161     |-    else\
+160     |-    else\
-162     |-        :  # comment
+161     |-        :\
+162     |-        # comment
 163     |-        pass
-    161 |+    # comment
+    160 |+    # comment
-    162 |+    pass
+    161 |+    pass
-164 163 | 
+164 162 | 
-165 164 | 
+165 163 | 
-166 165 | def bar8():
+166 164 | def bar7():
 
 RET505.py:169:5: RET505 [*] Unnecessary `else` after `return` statement
     |
 167 |     if True:
 168 |         return
-169 |     else: pass
+169 |     else\
     |     ^^^^ RET505
+170 |         :  # comment
+171 |         pass
     |
     = help: Remove unnecessary `else`
 
 ℹ Safe fix
-166 166 | def bar8():
+166 166 | def bar7():
 167 167 |     if True:
 168 168 |         return
-169     |-    else: pass
+169     |-    else\
-    169 |+    pass
+170     |-        :  # comment
-170 170 | 
+171     |-        pass
-171 171 | 
+    169 |+    # comment
-172 172 | def bar9():
+    170 |+    pass
+172 171 | 
+173 172 | 
+174 173 | def bar8():
 
-RET505.py:175:5: RET505 [*] Unnecessary `else` after `return` statement
+RET505.py:177:5: RET505 [*] Unnecessary `else` after `return` statement
     |
-173 |     if True:
+175 |     if True:
-174 |         return
+176 |         return
-175 |     else:\
+177 |     else: pass
     |     ^^^^ RET505
-176 |         pass
     |
     = help: Remove unnecessary `else`
 
 ℹ Safe fix
-172 172 | def bar9():
+174 174 | def bar8():
-173 173 |     if True:
+175 175 |     if True:
-174 174 |         return
+176 176 |         return
-175     |-    else:\
+177     |-    else: pass
-176     |-        pass
+    177 |+    pass
-    175 |+    pass
+178 178 | 
-177 176 | 
+179 179 | 
-178 177 | 
+180 180 | def bar9():
-179 178 | x = 0
+
+RET505.py:183:5: RET505 [*] Unnecessary `else` after `return` statement
+    |
+181 |     if True:
+182 |         return
+183 |     else:\
+    |     ^^^^ RET505
+184 |         pass
+    |
+    = help: Remove unnecessary `else`
+
+ℹ Safe fix
+180 180 | def bar9():
+181 181 |     if True:
+182 182 |         return
+183     |-    else:\
+184     |-        pass
+    183 |+    pass
+185 184 | 
+186 185 | 
+187 186 | x = 0