Merge #4743

4743: Add tracking of packed repr, use it to highlight unsafe refs r=matklad a=Nashenas88

Taking a reference to a misaligned field on a packed struct is an
unsafe operation. Highlight that behavior. Currently, the misaligned
part isn't tracked, so this highlight is a bit too aggressive.

Fixes #4600

Co-authored-by: Paul Daniel Faria <[email protected]>
Co-authored-by: Paul Daniel Faria <[email protected]>
Co-authored-by: Paul Daniel Faria <[email protected]>

1 files changed, 30 insertions, 3 deletions

diff --git a/crates/ra_ide/test_data/highlight_unsafe.html b/crates/ra_ide/test_data/highlight_unsafe.html
index 79409fe81..552fea668 100644
--- a/crates/ra_ide/test_data/highlight_unsafe.html
+++ b/crates/ra_ide/test_data/highlight_unsafe.html
@@ -54,10 +54,24 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 
 <span class="keyword">static</span> <span class="keyword">mut</span> <span class="static declaration mutable unsafe">global_mut</span><span class="punctuation">:</span> <span class="struct">TypeForStaticMut</span> <span class="operator">=</span> <span class="struct">TypeForStaticMut</span> <span class="punctuation">{</span> <span class="field">a</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span><span class="punctuation">;</span>
 
+<span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">repr</span><span class="punctuation">(</span><span class="attribute">packed</span><span class="punctuation">)</span><span class="attribute">]</span>
+<span class="keyword">struct</span> <span class="struct declaration">Packed</span> <span class="punctuation">{</span>
+    <span class="field declaration">a</span><span class="punctuation">:</span> <span class="builtin_type">u16</span><span class="punctuation">,</span>
+<span class="punctuation">}</span>
+
+<span class="keyword">trait</span> <span class="trait declaration">DoTheAutoref</span> <span class="punctuation">{</span>
+    <span class="keyword">fn</span> <span class="function declaration">calls_autoref</span><span class="punctuation">(</span><span class="operator">&</span><span class="self_keyword">self</span><span class="punctuation">)</span><span class="punctuation">;</span>
+<span class="punctuation">}</span>
+
+<span class="keyword">impl</span> <span class="trait">DoTheAutoref</span> <span class="keyword">for</span> <span class="builtin_type">u16</span> <span class="punctuation">{</span>
+    <span class="keyword">fn</span> <span class="function declaration">calls_autoref</span><span class="punctuation">(</span><span class="operator">&</span><span class="self_keyword">self</span><span class="punctuation">)</span> <span class="punctuation">{</span><span class="punctuation">}</span>
+<span class="punctuation">}</span>
+
 <span class="keyword">fn</span> <span class="function declaration">main</span><span class="punctuation">(</span><span class="punctuation">)</span> <span class="punctuation">{</span>
-    <span class="keyword">let</span> <span class="variable declaration">x</span> <span class="operator">=</span> <span class="operator">&</span><span class="numeric_literal">5</span> <span class="keyword">as</span> <span class="keyword">*</span><span class="keyword">const</span> <span class="builtin_type">usize</span><span class="punctuation">;</span>
+    <span class="keyword">let</span> <span class="variable declaration">x</span> <span class="operator">=</span> <span class="operator">&</span><span class="numeric_literal">5</span> <span class="keyword">as</span> <span class="keyword">*</span><span class="keyword">const</span> <span class="punctuation">_</span> <span class="keyword">as</span> <span class="keyword">*</span><span class="keyword">const</span> <span class="builtin_type">usize</span><span class="punctuation">;</span>
     <span class="keyword">let</span> <span class="variable declaration">u</span> <span class="operator">=</span> <span class="union">Union</span> <span class="punctuation">{</span> <span class="field">b</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span><span class="punctuation">;</span>
     <span class="keyword unsafe">unsafe</span> <span class="punctuation">{</span>
+        <span class="comment">// unsafe fn and method calls</span>
         <span class="function unsafe">unsafe_fn</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
         <span class="keyword">let</span> <span class="variable declaration">b</span> <span class="operator">=</span> <span class="variable">u</span><span class="punctuation">.</span><span class="field unsafe">b</span><span class="punctuation">;</span>
         <span class="keyword control">match</span> <span class="variable">u</span> <span class="punctuation">{</span>
@@ -65,8 +79,21 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
             <span class="union">Union</span> <span class="punctuation">{</span> <span class="field unsafe">a</span> <span class="punctuation">}</span> <span class="operator">=&gt;</span> <span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">,</span>
         <span class="punctuation">}</span>
         <span class="struct">HasUnsafeFn</span><span class="punctuation">.</span><span class="function unsafe">unsafe_method</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
-        <span class="keyword">let</span> <span class="variable declaration">y</span> <span class="operator">=</span> <span class="operator unsafe">*</span><span class="punctuation">(</span><span class="variable">x</span><span class="punctuation">)</span><span class="punctuation">;</span>
-        <span class="keyword">let</span> <span class="variable declaration">z</span> <span class="operator">=</span> <span class="numeric_literal">-</span><span class="variable">x</span><span class="punctuation">;</span>
+
+        <span class="comment">// unsafe deref</span>
+        <span class="keyword">let</span> <span class="variable declaration">y</span> <span class="operator">=</span> <span class="operator unsafe">*</span><span class="variable">x</span><span class="punctuation">;</span>
+
+        <span class="comment">// unsafe access to a static mut</span>
         <span class="keyword">let</span> <span class="variable declaration">a</span> <span class="operator">=</span> <span class="static mutable unsafe">global_mut</span><span class="punctuation">.</span><span class="field">a</span><span class="punctuation">;</span>
+
+        <span class="comment">// unsafe ref of packed fields</span>
+        <span class="keyword">let</span> <span class="variable declaration">packed</span> <span class="operator">=</span> <span class="struct">Packed</span> <span class="punctuation">{</span> <span class="field">a</span><span class="punctuation">:</span> <span class="numeric_literal">0</span> <span class="punctuation">}</span><span class="punctuation">;</span>
+        <span class="keyword">let</span> <span class="variable declaration">a</span> <span class="operator">=</span> <span class="operator unsafe">&</span><span class="variable">packed</span><span class="punctuation">.</span><span class="field">a</span><span class="punctuation">;</span>
+        <span class="keyword">let</span> <span class="keyword unsafe">ref</span> <span class="variable declaration">a</span> <span class="operator">=</span> <span class="variable">packed</span><span class="punctuation">.</span><span class="field">a</span><span class="punctuation">;</span>
+        <span class="keyword">let</span> <span class="struct">Packed</span> <span class="punctuation">{</span> <span class="keyword unsafe">ref</span> <span class="field">a</span> <span class="punctuation">}</span> <span class="operator">=</span> <span class="variable">packed</span><span class="punctuation">;</span>
+        <span class="keyword">let</span> <span class="struct">Packed</span> <span class="punctuation">{</span> <span class="field">a</span><span class="punctuation">:</span> <span class="keyword unsafe">ref</span> <span class="variable declaration">_a</span> <span class="punctuation">}</span> <span class="operator">=</span> <span class="variable">packed</span><span class="punctuation">;</span>
+
+        <span class="comment">// unsafe auto ref of packed field</span>
+        <span class="variable">packed</span><span class="punctuation">.</span><span class="field">a</span><span class="punctuation">.</span><span class="function unsafe">calls_autoref</span><span class="punctuation">(</span><span class="punctuation">)</span><span class="punctuation">;</span>
     <span class="punctuation">}</span>
 <span class="punctuation">}</span></code></pre>
\ No newline at end of file