coverage: Handle fn signature spans more consistently near ?

Author: Zalathar

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -80,7 +80,7 @@ impl CoverageSpan {
             expn_span: fn_sig_span,
             current_macro_or_none: Default::default(),
             bcb: START_BCB,
-            merged_spans: vec![],
+            merged_spans: vec![fn_sig_span],
             is_closure: false,
         }
     }

tests/coverage-map/fn_sig_into_try.cov-map

@@ -7,30 +7,30 @@ Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 10, 1) to (start + 4, 2)
 
 Function name: fn_sig_into_try::b
-Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 12, 05, 00, 0f, 00, 00, 0f, 00, 10, 02, 01, 05, 00, 0c, 07, 01, 01, 00, 02]
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 10, 01, 02, 0f, 00, 02, 0f, 00, 10, 02, 01, 05, 00, 0c, 07, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => global file 1
 Number of expressions: 2
 - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
 - expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
 Number of file 0 mappings: 4
-- Code(Counter(0)) at (prev + 18, 5) to (start + 0, 15)
-- Code(Zero) at (prev + 0, 15) to (start + 0, 16)
+- Code(Counter(0)) at (prev + 16, 1) to (start + 2, 15)
+- Code(Zero) at (prev + 2, 15) to (start + 0, 16)
 - Code(Expression(0, Sub)) at (prev + 1, 5) to (start + 0, 12)
     = (c0 - c1)
 - Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
     = (c1 + (c0 - c1))
 
 Function name: fn_sig_into_try::c
-Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 18, 0d, 00, 17, 00, 00, 17, 00, 18, 02, 01, 05, 00, 0c, 07, 01, 01, 00, 02]
+Raw bytes (28): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 16, 01, 02, 17, 00, 02, 17, 00, 18, 02, 01, 05, 00, 0c, 07, 01, 01, 00, 02]
 Number of files: 1
 - file 0 => global file 1
 Number of expressions: 2
 - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
 - expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
 Number of file 0 mappings: 4
-- Code(Counter(0)) at (prev + 24, 13) to (start + 0, 23)
-- Code(Zero) at (prev + 0, 23) to (start + 0, 24)
+- Code(Counter(0)) at (prev + 22, 1) to (start + 2, 23)
+- Code(Zero) at (prev + 2, 23) to (start + 0, 24)
 - Code(Expression(0, Sub)) at (prev + 1, 5) to (start + 0, 12)
     = (c0 - c1)
 - Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)

tests/coverage-map/status-quo/inline-dead.cov-map

@@ -31,13 +31,15 @@ Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 7, 6) to (start + 2, 2)
 
 Function name: inline_dead::main::{closure#0}
-Raw bytes (16): 0x[01, 01, 01, 01, 05, 02, 00, 09, 0d, 00, 0e, 03, 02, 05, 00, 06]
+Raw bytes (23): 0x[01, 01, 02, 09, 06, 01, 05, 03, 01, 07, 17, 00, 18, 00, 02, 0d, 00, 0e, 03, 02, 05, 00, 06]
 Number of files: 1
 - file 0 => global file 1
-Number of expressions: 1
-- expression 0 operands: lhs = Counter(0), rhs = Counter(1)
-Number of file 0 mappings: 2
-- Code(Zero) at (prev + 9, 13) to (start + 0, 14)
+Number of expressions: 2
+- expression 0 operands: lhs = Counter(2), rhs = Expression(1, Sub)
+- expression 1 operands: lhs = Counter(0), rhs = Counter(1)
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 7, 23) to (start + 0, 24)
+- Code(Zero) at (prev + 2, 13) to (start + 0, 14)
 - Code(Expression(0, Add)) at (prev + 2, 5) to (start + 0, 6)
-    = (c0 + c1)
+    = (c2 + (c0 - c1))
 

tests/coverage-map/status-quo/issue-84561.cov-map

@@ -7,15 +7,15 @@ Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 4, 10) to (start + 0, 19)
 
 Function name: <issue_84561::Foo as core::fmt::Debug>::fmt
-Raw bytes (29): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 89, 01, 09, 00, 25, 05, 00, 25, 00, 26, 02, 01, 09, 00, 0f, 07, 01, 05, 00, 06]
+Raw bytes (29): 0x[01, 01, 02, 01, 05, 05, 02, 04, 01, 88, 01, 05, 01, 25, 05, 01, 25, 00, 26, 02, 01, 09, 00, 0f, 07, 01, 05, 00, 06]
 Number of files: 1
 - file 0 => global file 1
 Number of expressions: 2
 - expression 0 operands: lhs = Counter(0), rhs = Counter(1)
 - expression 1 operands: lhs = Counter(1), rhs = Expression(0, Sub)
 Number of file 0 mappings: 4
-- Code(Counter(0)) at (prev + 137, 9) to (start + 0, 37)
-- Code(Counter(1)) at (prev + 0, 37) to (start + 0, 38)
+- Code(Counter(0)) at (prev + 136, 5) to (start + 1, 37)
+- Code(Counter(1)) at (prev + 1, 37) to (start + 0, 38)
 - Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 15)
     = (c0 - c1)
 - Code(Expression(1, Add)) at (prev + 1, 5) to (start + 0, 6)

tests/run-coverage/fn_sig_into_try.coverage

@@ -13,15 +13,15 @@
    LL|      1|    Some(0)
    LL|      1|}
    LL|       |
-   LL|       |fn b() -> Option<i32>
-   LL|       |{
+   LL|      1|fn b() -> Option<i32>
+   LL|      1|{
    LL|      1|    Some(7i32)?;
                             ^0
    LL|      1|    Some(0)
    LL|      1|}
    LL|       |
-   LL|       |fn c() -> Option<i32>
-   LL|       |{
+   LL|      1|fn c() -> Option<i32>
+   LL|      1|{
    LL|      1|    let _ = Some(7i32)?;
                                     ^0
    LL|      1|    Some(0)

tests/run-coverage/issue-84561.coverage

@@ -135,7 +135,7 @@
    LL|      0|}
    LL|       |
    LL|       |impl std::fmt::Debug for Foo {
-   LL|       |    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+   LL|      7|    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
    LL|      7|        write!(f, "try and succeed")?;
                                                   ^0
    LL|      7|        Ok(())