Unrolled build for #148465

Rollup merge of #148465 - Jarcho:for_span, r=davidtwco,Zalathar

Adjust spans into the `for` loops context before creating the new desugaring spans.

When lowering `for` loops, the spans for the `into_iter` call and the `Some` pattern used the span of the provided pattern and head expression. If either of those came from a different `SyntaxContext` this would result in some very strange contexts. e.g.:

```rust
macro_rules! m { ($e:expr) => { { $e } } }
for _ in m!(expr) {}
```

This would result in the `into_iter` call have a context chain of `desugar => m!() => root` which is completely nonsensical; `m!()`  does not have a `for` loop. The `into_iter` call also ends up located at `{ $e }` rather than inside the `for _ in _` part.

This fixes that by walking the spans up to the `for` loop's context first. This will not handle adjusting the location of macro variable expansions (e.g. `for _ in $e`), but this does adjust the context to match the `for` loops.

---

This ended up causing rust-lang/rust-clippy#16008. Clippy should be using a `debug_assert` rather than `unreachable`, but it still results in a bug either way.

Author: rust-timer

compiler/rustc_ast_lowering/src/expr.rs

@@ -1771,8 +1771,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let pat = self.lower_pat(pat);
         let for_span =
             self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
-        let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
-        let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
+        let for_ctxt = for_span.ctxt();
+
+        // Try to point both the head and pat spans to their position in the for loop
+        // rather than inside a macro.
+        let head_span =
+            head.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(head.span).with_ctxt(for_ctxt);
+        let pat_span =
+            pat.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(pat.span).with_ctxt(for_ctxt);
 
         let loop_hir_id = self.lower_node_id(e.id);
         let label = self.lower_label(opt_label, e.id, loop_hir_id);

tests/coverage/async_block.cov-map

@@ -1,5 +1,5 @@
 Function name: async_block::main
-Raw bytes (41): 0x[01, 01, 01, 05, 01, 07, 01, 07, 01, 00, 0a, 02, 01, 09, 00, 0a, 05, 00, 0e, 00, 13, 02, 01, 0d, 00, 13, 02, 07, 09, 00, 1b, 02, 00, 1c, 00, 22, 01, 02, 01, 00, 02]
+Raw bytes (41): 0x[01, 01, 01, 05, 01, 07, 01, 07, 01, 00, 0a, 02, 01, 09, 00, 0a, 01, 00, 0e, 00, 13, 02, 01, 0d, 00, 13, 02, 07, 09, 00, 1b, 02, 00, 1c, 00, 22, 01, 02, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/async_block.rs
 Number of expressions: 1
@@ -8,15 +8,15 @@ Number of file 0 mappings: 7
 - Code(Counter(0)) at (prev + 7, 1) to (start + 0, 10)
 - Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 10)
     = (c1 - c0)
-- Code(Counter(1)) at (prev + 0, 14) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 0, 14) to (start + 0, 19)
 - Code(Expression(0, Sub)) at (prev + 1, 13) to (start + 0, 19)
     = (c1 - c0)
 - Code(Expression(0, Sub)) at (prev + 7, 9) to (start + 0, 27)
     = (c1 - c0)
 - Code(Expression(0, Sub)) at (prev + 0, 28) to (start + 0, 34)
     = (c1 - c0)
 - Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
-Highest counter ID seen: c1
+Highest counter ID seen: c0
 
 Function name: async_block::main::{closure#0}
 Raw bytes (31): 0x[01, 01, 01, 01, 05, 05, 01, 09, 1c, 00, 1d, 01, 01, 10, 00, 17, 05, 00, 18, 02, 0e, 02, 02, 14, 02, 0e, 01, 03, 09, 00, 0a]

tests/coverage/async_block.coverage

@@ -5,8 +5,8 @@
    LL|       |extern crate executor;
    LL|       |
    LL|      1|fn main() {
-   LL|     17|    for i in 0..16 {
-                      ^16
+   LL|     16|    for i in 0..16 {
+                           ^1
    LL|     16|        let future = async {
    LL|     16|            if i >= 12 {
    LL|      4|                println!("big");

tests/coverage/continue.cov-map

@@ -1,5 +1,5 @@
 Function name: continue::main
-Raw bytes (241): 0x[01, 01, 1a, 05, 01, 05, 13, 01, 09, 05, 13, 01, 09, 0d, 01, 0d, 27, 01, 11, 0d, 27, 01, 11, 15, 01, 15, 33, 01, 19, 1d, 01, 1d, 47, 01, 21, 1d, 47, 01, 21, 25, 01, 25, 53, 01, 29, 25, 01, 2d, 01, 63, 2d, 01, 31, 2d, 01, 25, 01, 03, 01, 00, 0a, 01, 01, 09, 00, 10, 01, 00, 13, 00, 2e, 01, 02, 09, 00, 0e, 01, 00, 11, 00, 12, 05, 01, 0e, 00, 13, 02, 01, 0f, 00, 16, 09, 02, 11, 00, 19, 0e, 02, 12, 02, 0e, 0e, 04, 09, 00, 0e, 0d, 02, 0e, 00, 13, 16, 01, 0f, 00, 16, 22, 01, 16, 02, 0e, 11, 04, 11, 00, 19, 22, 03, 09, 00, 0e, 15, 02, 0e, 00, 13, 2a, 01, 0f, 00, 16, 19, 01, 15, 02, 0e, 2e, 04, 11, 00, 19, 19, 03, 09, 00, 0e, 1d, 02, 0e, 00, 13, 36, 01, 0c, 00, 13, 21, 01, 0d, 00, 15, 42, 01, 09, 00, 0a, 42, 01, 09, 00, 0e, 25, 02, 0e, 00, 13, 56, 01, 0f, 00, 16, 4e, 01, 16, 02, 0e, 29, 03, 12, 02, 0e, 56, 04, 09, 00, 0e, 2d, 02, 0e, 00, 13, 31, 01, 0f, 00, 16, 66, 01, 16, 02, 0e, 5e, 04, 11, 00, 16, 66, 03, 09, 00, 0e, 01, 02, 0d, 00, 0e, 01, 01, 01, 00, 02]
+Raw bytes (241): 0x[01, 01, 1a, 05, 01, 05, 13, 01, 09, 05, 13, 01, 09, 0d, 01, 0d, 27, 01, 11, 0d, 27, 01, 11, 15, 01, 15, 33, 01, 19, 1d, 01, 1d, 47, 01, 21, 1d, 47, 01, 21, 25, 01, 25, 53, 01, 29, 25, 01, 31, 01, 63, 31, 01, 2d, 31, 01, 25, 01, 03, 01, 00, 0a, 01, 01, 09, 00, 10, 01, 00, 13, 00, 2e, 01, 02, 09, 00, 0e, 01, 00, 11, 00, 12, 01, 01, 0e, 00, 13, 02, 01, 0f, 00, 16, 09, 02, 11, 00, 19, 0e, 02, 12, 02, 0e, 0e, 04, 09, 00, 0e, 01, 02, 0e, 00, 13, 16, 01, 0f, 00, 16, 22, 01, 16, 02, 0e, 11, 04, 11, 00, 19, 22, 03, 09, 00, 0e, 01, 02, 0e, 00, 13, 2a, 01, 0f, 00, 16, 19, 01, 15, 02, 0e, 2e, 04, 11, 00, 19, 19, 03, 09, 00, 0e, 01, 02, 0e, 00, 13, 36, 01, 0c, 00, 13, 21, 01, 0d, 00, 15, 42, 01, 09, 00, 0a, 42, 01, 09, 00, 0e, 01, 02, 0e, 00, 13, 56, 01, 0f, 00, 16, 4e, 01, 16, 02, 0e, 29, 03, 12, 02, 0e, 56, 04, 09, 00, 0e, 01, 02, 0e, 00, 13, 2d, 01, 0f, 00, 16, 66, 01, 16, 02, 0e, 5e, 04, 11, 00, 16, 66, 03, 09, 00, 0e, 01, 02, 0d, 00, 0e, 01, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/continue.rs
 Number of expressions: 26
@@ -25,64 +25,64 @@ Number of expressions: 26
 - expression 19 operands: lhs = Counter(9), rhs = Expression(20, Add)
 - expression 20 operands: lhs = Counter(0), rhs = Counter(10)
 - expression 21 operands: lhs = Counter(9), rhs = Counter(0)
-- expression 22 operands: lhs = Counter(11), rhs = Counter(0)
-- expression 23 operands: lhs = Expression(24, Add), rhs = Counter(11)
-- expression 24 operands: lhs = Counter(0), rhs = Counter(12)
-- expression 25 operands: lhs = Counter(11), rhs = Counter(0)
+- expression 22 operands: lhs = Counter(12), rhs = Counter(0)
+- expression 23 operands: lhs = Expression(24, Add), rhs = Counter(12)
+- expression 24 operands: lhs = Counter(0), rhs = Counter(11)
+- expression 25 operands: lhs = Counter(12), rhs = Counter(0)
 Number of file 0 mappings: 37
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 10)
 - Code(Counter(0)) at (prev + 1, 9) to (start + 0, 16)
 - Code(Counter(0)) at (prev + 0, 19) to (start + 0, 46)
 - Code(Counter(0)) at (prev + 2, 9) to (start + 0, 14)
 - Code(Counter(0)) at (prev + 0, 17) to (start + 0, 18)
-- Code(Counter(1)) at (prev + 1, 14) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 1, 14) to (start + 0, 19)
 - Code(Expression(0, Sub)) at (prev + 1, 15) to (start + 0, 22)
     = (c1 - c0)
 - Code(Counter(2)) at (prev + 2, 17) to (start + 0, 25)
 - Code(Expression(3, Sub)) at (prev + 2, 18) to (start + 2, 14)
     = (c1 - (c0 + c2))
 - Code(Expression(3, Sub)) at (prev + 4, 9) to (start + 0, 14)
     = (c1 - (c0 + c2))
-- Code(Counter(3)) at (prev + 2, 14) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 2, 14) to (start + 0, 19)
 - Code(Expression(5, Sub)) at (prev + 1, 15) to (start + 0, 22)
     = (c3 - c0)
 - Code(Expression(8, Sub)) at (prev + 1, 22) to (start + 2, 14)
     = (c3 - (c0 + c4))
 - Code(Counter(4)) at (prev + 4, 17) to (start + 0, 25)
 - Code(Expression(8, Sub)) at (prev + 3, 9) to (start + 0, 14)
     = (c3 - (c0 + c4))
-- Code(Counter(5)) at (prev + 2, 14) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 2, 14) to (start + 0, 19)
 - Code(Expression(10, Sub)) at (prev + 1, 15) to (start + 0, 22)
     = (c5 - c0)
 - Code(Counter(6)) at (prev + 1, 21) to (start + 2, 14)
 - Code(Expression(11, Sub)) at (prev + 4, 17) to (start + 0, 25)
     = (c5 - (c0 + c6))
 - Code(Counter(6)) at (prev + 3, 9) to (start + 0, 14)
-- Code(Counter(7)) at (prev + 2, 14) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 2, 14) to (start + 0, 19)
 - Code(Expression(13, Sub)) at (prev + 1, 12) to (start + 0, 19)
     = (c7 - c0)
 - Code(Counter(8)) at (prev + 1, 13) to (start + 0, 21)
 - Code(Expression(16, Sub)) at (prev + 1, 9) to (start + 0, 10)
     = (c7 - (c0 + c8))
 - Code(Expression(16, Sub)) at (prev + 1, 9) to (start + 0, 14)
     = (c7 - (c0 + c8))
-- Code(Counter(9)) at (prev + 2, 14) to (start + 0, 19)
+- Code(Counter(0)) at (prev + 2, 14) to (start + 0, 19)
 - Code(Expression(21, Sub)) at (prev + 1, 15) to (start + 0, 22)
     = (c9 - c0)
 - Code(Expression(19, Sub)) at (prev + 1, 22) to (start + 2, 14)
     = (c9 - (c0 + c10))
 - Code(Counter(10)) at (prev + 3, 18) to (start + 2, 14)
 - Code(Expression(21, Sub)) at (prev + 4, 9) to (start + 0, 14)
     = (c9 - c0)
-- Code(Counter(11)) at (prev + 2, 14) to (start + 0, 19)
-- Code(Counter(12)) at (prev + 1, 15) to (start + 0, 22)
+- Code(Counter(0)) at (prev + 2, 14) to (start + 0, 19)
+- Code(Counter(11)) at (prev + 1, 15) to (start + 0, 22)
 - Code(Expression(25, Sub)) at (prev + 1, 22) to (start + 2, 14)
-    = (c11 - c0)
+    = (c12 - c0)
 - Code(Expression(23, Sub)) at (prev + 4, 17) to (start + 0, 22)
-    = ((c0 + c12) - c11)
+    = ((c0 + c11) - c12)
 - Code(Expression(25, Sub)) at (prev + 3, 9) to (start + 0, 14)
-    = (c11 - c0)
+    = (c12 - c0)
 - Code(Counter(0)) at (prev + 2, 13) to (start + 0, 14)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
-Highest counter ID seen: c12
+Highest counter ID seen: c11
 

tests/coverage/continue.coverage

@@ -4,7 +4,7 @@
    LL|      1|    let is_true = std::env::args().len() == 1;
    LL|       |
    LL|      1|    let mut x = 0;
-   LL|     11|    for _ in 0..10 {
+   LL|      1|    for _ in 0..10 {
    LL|     10|        match is_true {
    LL|       |            true => {
    LL|     10|                continue;
@@ -15,7 +15,7 @@
    LL|       |        }
    LL|      0|        x = 3;
    LL|       |    }
-   LL|     11|    for _ in 0..10 {
+   LL|      1|    for _ in 0..10 {
    LL|     10|        match is_true {
    LL|      0|            false => {
    LL|      0|                x = 1;
@@ -26,7 +26,7 @@
    LL|       |        }
    LL|      0|        x = 3;
    LL|       |    }
-   LL|     11|    for _ in 0..10 {
+   LL|      1|    for _ in 0..10 {
    LL|     10|        match is_true {
    LL|     10|            true => {
    LL|     10|                x = 1;
@@ -37,13 +37,13 @@
    LL|       |        }
    LL|     10|        x = 3;
    LL|       |    }
-   LL|     11|    for _ in 0..10 {
+   LL|      1|    for _ in 0..10 {
    LL|     10|        if is_true {
    LL|     10|            continue;
    LL|      0|        }
    LL|      0|        x = 3;
    LL|       |    }
-   LL|     11|    for _ in 0..10 {
+   LL|      1|    for _ in 0..10 {
    LL|     10|        match is_true {
    LL|      0|            false => {
    LL|      0|                x = 1;

tests/coverage/inline.cov-map

@@ -1,5 +1,5 @@
 Function name: inline::display::<char>
-Raw bytes (36): 0x[01, 01, 01, 05, 01, 06, 01, 29, 01, 00, 21, 02, 01, 09, 00, 0a, 05, 00, 0e, 00, 10, 02, 00, 11, 02, 06, 01, 03, 05, 00, 0d, 01, 01, 01, 00, 02]
+Raw bytes (36): 0x[01, 01, 01, 05, 01, 06, 01, 29, 01, 00, 21, 02, 01, 09, 00, 0a, 01, 00, 0e, 00, 10, 02, 00, 11, 02, 06, 01, 03, 05, 00, 0d, 01, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/inline.rs
 Number of expressions: 1
@@ -8,12 +8,12 @@ Number of file 0 mappings: 6
 - Code(Counter(0)) at (prev + 41, 1) to (start + 0, 33)
 - Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 10)
     = (c1 - c0)
-- Code(Counter(1)) at (prev + 0, 14) to (start + 0, 16)
+- Code(Counter(0)) at (prev + 0, 14) to (start + 0, 16)
 - Code(Expression(0, Sub)) at (prev + 0, 17) to (start + 2, 6)
     = (c1 - c0)
 - Code(Counter(0)) at (prev + 3, 5) to (start + 0, 13)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
-Highest counter ID seen: c1
+Highest counter ID seen: c0
 
 Function name: inline::error
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 31, 01, 00, 0b, 01, 01, 05, 00, 0b]
@@ -50,7 +50,7 @@ Number of file 0 mappings: 4
 Highest counter ID seen: c0
 
 Function name: inline::permutate::<char>
-Raw bytes (142): 0x[01, 01, 0e, 01, 05, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 01, 37, 05, 09, 16, 01, 0f, 01, 00, 38, 01, 01, 09, 00, 0a, 01, 00, 0d, 00, 13, 01, 00, 14, 00, 16, 01, 01, 08, 00, 0e, 05, 00, 0f, 02, 06, 02, 02, 0f, 00, 14, 2e, 01, 0d, 00, 0e, 09, 00, 12, 00, 13, 09, 00, 15, 00, 16, 2e, 00, 17, 04, 0a, 2e, 01, 0d, 00, 11, 2e, 00, 12, 00, 14, 2e, 00, 16, 00, 17, 2e, 00, 19, 00, 1a, 2e, 01, 0d, 00, 16, 2e, 00, 17, 00, 19, 2e, 00, 1b, 00, 20, 2e, 01, 0d, 00, 11, 2e, 00, 12, 00, 14, 32, 02, 0c, 02, 06, 01, 03, 01, 00, 02]
+Raw bytes (137): 0x[01, 01, 0e, 01, 05, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 0d, 09, 01, 37, 05, 09, 15, 01, 0f, 01, 00, 38, 01, 01, 09, 00, 0a, 01, 00, 0d, 00, 13, 01, 00, 14, 00, 16, 01, 01, 08, 00, 0e, 05, 00, 0f, 02, 06, 02, 02, 0f, 00, 14, 2e, 01, 0d, 00, 0e, 09, 00, 12, 00, 16, 2e, 00, 17, 04, 0a, 2e, 01, 0d, 00, 11, 2e, 00, 12, 00, 14, 2e, 00, 16, 00, 17, 2e, 00, 19, 00, 1a, 2e, 01, 0d, 00, 16, 2e, 00, 17, 00, 19, 2e, 00, 1b, 00, 20, 2e, 01, 0d, 00, 11, 2e, 00, 12, 00, 14, 32, 02, 0c, 02, 06, 01, 03, 01, 00, 02]
 Number of files: 1
 - file 0 => $DIR/inline.rs
 Number of expressions: 14
@@ -68,7 +68,7 @@ Number of expressions: 14
 - expression 11 operands: lhs = Counter(3), rhs = Counter(2)
 - expression 12 operands: lhs = Counter(0), rhs = Expression(13, Add)
 - expression 13 operands: lhs = Counter(1), rhs = Counter(2)
-Number of file 0 mappings: 22
+Number of file 0 mappings: 21
 - Code(Counter(0)) at (prev + 15, 1) to (start + 0, 56)
 - Code(Counter(0)) at (prev + 1, 9) to (start + 0, 10)
 - Code(Counter(0)) at (prev + 0, 13) to (start + 0, 19)
@@ -79,8 +79,7 @@ Number of file 0 mappings: 22
     = (c0 - c1)
 - Code(Expression(11, Sub)) at (prev + 1, 13) to (start + 0, 14)
     = (c3 - c2)
-- Code(Counter(2)) at (prev + 0, 18) to (start + 0, 19)
-- Code(Counter(2)) at (prev + 0, 21) to (start + 0, 22)
+- Code(Counter(2)) at (prev + 0, 18) to (start + 0, 22)
 - Code(Expression(11, Sub)) at (prev + 0, 23) to (start + 4, 10)
     = (c3 - c2)
 - Code(Expression(11, Sub)) at (prev + 1, 13) to (start + 0, 17)

tests/coverage/inline.coverage

@@ -18,7 +18,7 @@
    LL|      6|        display(xs);
    LL|     10|    } else if k < n {
    LL|     15|        for i in k..n {
-                               ^10^10
+                               ^10
    LL|     15|            swap(xs, i, k);
    LL|     15|            permutate(xs, k + 1);
    LL|     15|            swap(xs, i, k);
@@ -40,8 +40,8 @@
    LL|     30|}
    LL|       |
    LL|      6|fn display<T: Display>(xs: &[T]) {
-   LL|     24|    for x in xs {
-                      ^18
+   LL|     18|    for x in xs {
+                           ^6
    LL|     18|        print!("{}", x);
    LL|     18|    }
    LL|      6|    println!();